JPH10158567A - Black ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a black ink composition that can simply be washed out with water, etc., even in the case of attaching the ink to clothing by mistake, excellent in bleeding, transfer, concentration, holograph characteristics, etc., comprising a readily eliminable colorant and water. SOLUTION: This composition comprises preferably 20-40wt.% of a readily eliminable colorant of a compound of the formula R-[(CH2 CH2 O)n H]x (R is a dye group; (n) is >=15; (x) is 1-16; the product of (n) and (x) is 30-200), water, 3-8wt.% of a polyvinyl alcohol having <=3.5-16.0Pa.S viscosity in 4wt.% of an aqueous solution (at 20 deg.C), 300-2,000 polymerization degree and 87-89mol% saponification degree or 4-12wt.% of a polyvinylpyrrolidone as a fixing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ink composition. More specifically, the present invention relates to a black ink composition that can be easily erased by washing with water even if it accidentally adheres to clothes or the like.

[0002]

2. Description of the Related Art Ink is usually produced by adding glue or the like to a colorant such as carbon black.
Such an additive is added for imparting viscosity to ink and preventing bleeding on paper and the like, and also improves fixability to an object to be coated such as paper.

[0003]

Therefore, when the ink is accidentally attached to clothes, fine particles of a colorant of black ink such as carbon black tend to be caught in the eyes of the fibers, so that it cannot be erased cleanly. There is a problem that stains and stains adhere to the surface. In order to solve this problem, it is conceivable to adjust the raw material, composition, and the like. However, the problem such as excessive bleeding on paper or the like also occurred, and the problem has not been completely solved.

[0004] It is an object of the present invention to solve the problem of the erasability of the conventional ink and to provide ink that does not blur even when written on paper or the like.

[0005]

The inventor of the present invention has made intensive studies to solve the problem of the elimination of ink, and as a result, completed the present invention. That is, the first aspect of the present invention is a black ink composition containing an easily erasable colorant and water. The easily erasable colorant referred to in the present invention is erasable by washing when attached to the fiber, and at the same time, has a sufficient coloring effect as ink, and has a low viscosity in the case of a liquid, for example, It is important that the viscosity is as low as 7 mPa · S or less.

[0006] As an easily erasable colorant suitably used in such a black ink composition, there is particularly an easily erasable colorant represented by the following general formula.

Embedded image (However, R is a dye group, n is 15 or more, X is 1 to 16,
The product of n and X is 30 to 200)

That is, it is a water-soluble polymer surfactant having at least 15 repeating units in the molecule, has a molecular weight of at least 1,000, and has a dye group R bonded to a polymer chain.
Is a compound having The dye group R corresponds to a colored portion, and examples thereof include those represented by the following chemical formula.

[0008]

Embedded image

[0009]

Embedded image

[0010] Specific easy-erasable colorants include Milliken Ch, which was originally used as a fiber sorting dye.
product name "VERSATINT"
Similarly, a marker ink brand name “PALMER” manufactured by Milliken Chemical Company is used, and it is desirable to use these easily erasable colorants, but there is no particular limitation.

The concentration of the easily erasable colorant is optimally 20 to 40% by weight (hereinafter simply abbreviated as%) when applied for ink. That is, the invention according to claim 3 is the ink composition according to claim 1 or 2, which contains an easily erasable colorant in an amount of 20 to 40% by weight.

The reason for limiting the concentration is to ensure that the ink has a sufficient density as ink and has an acceptable viscosity as ink. That is, if the concentration is lower than this range, sufficient coloring cannot be expected, and it is not suitable for use as ink.

Further, the present inventor has found that by adding a fixing agent to the above ink, it is possible to prevent bleeding on paper while maintaining the erasability. That is, the invention according to claim 4 is the ink composition according to claims 1, 2 or 3 containing a fixing agent.

As the ink composition, the conditions required for such a fixing agent are that it is soluble in water or hot water, that the aqueous solution has a low viscosity (65 mPa · S or less in an 8% aqueous solution), and that it has fixability. It is mentioned that it is.

Specifically, besides glue and gelatin, water-soluble resins such as polyvinyl alcohol and polyvinyl pyrrolidone can be suitably used. In particular, when an easily erasable colorant is contained as a black ink composition, polyvinyl alcohol or polyvinylpyrrolidone is suitable as a fixing agent. The invention according to claim 5 is the ink composition according to claim 4, wherein polyvinyl alcohol or polyvinylpyrrolidone is used as a fixing agent.

The reason for adding these fixing agents is to increase the viscosity of the ink to prevent bleeding on paper, but if the viscosity becomes too high, the brush character properties are lost, and It depends on the usability. Specifically, in the case of polyvinyl alcohol, the concentration of a 4% aqueous solution (20 ° C.) is preferably 3.5 to 16.0 mPa · S or less. The viscosity of the aqueous solution of polyvinyl alcohol depends not only on the concentration but also on the degree of polymerization and the degree of saponification of polyvinyl alcohol. Specifically, the degree of polymerization is 300 to 1000, and the degree of saponification is 87 to 89 mol%.
Is a 4% aqueous solution of polyvinyl alcohol,
The above is 3.5 to 16.0 mPa · S.

Conversely, if the addition amount is too small, it causes bleeding. That is, in the case of polyvinyl alcohol, 3 to
It is desirable that it is within the range of 8%, and in the case of polyvinylpyrrolidone, it is 4 to 12%. The invention according to claim 8 is the ink composition according to claim 5, 6 or 7 containing 3 to 8% of polyvinyl alcohol. Similarly, in the case of polyvinylpyrrolidone, the content is preferably 4 to 12%. According to the ninth aspect of the present invention, polyvinylpyrrolidone is used
The ink composition according to claim 5, which contains about 12%.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The ink of the present invention comprises at least an easily erasable colorant and water, and the aforementioned easily erasable colorant can be suitably used. However, the colorant is not limited to those described above, and any easily erasable colorant that satisfies all the above conditions can be used without any problem.

The amount of the dye added is preferably in the range of 20 to 40% based on the total amount of ink, and more preferably 2 to 40%.
The range of 6-38% is optimal. The specific amount of addition is preferably determined in consideration of the density and bleeding on paper,
As will be described later, the addition of a fixing agent can prevent bleeding on paper, so that there is no problem even if a large amount is added.

It is not necessary to use a single dye having a single color, and various colors may be produced by mixing the dyes. Specifically, for example, if a mixture of red and yellow dyes is used, orange ink can be produced.

The fixing agent to be added to the ink must satisfy the above conditions, and specifically, water-soluble resins such as polyvinyl alcohol and polyvinyl pyrrolidone can be suitably used. As the polyvinyl alcohol, a 4% aqueous solution having a low viscosity of 3.5 to 16.0 mpa · s is more preferable, and when this solution is obtained, the viscosity of the polyvinyl alcohol corresponds to 300 to 1000. Further, from the viewpoint of water solubility, the saponification degree is preferably 87 to 89 mol%. If the saponification degree is too low, the solubility is poor, and if it is too high, it swells and gels easily.

The amount of polyvinyl alcohol added is preferably 3 to 8%, more preferably 4 to 7%, based on the total amount of ink.

Similarly, polyvinylpyrrolidone preferably has a low viscosity, and preferably has a molecular weight of about 10,000 to 40,000. The addition amount is preferably in the range of 4 to 12%, more preferably 5 to 10%.

The ink which is usually added to the ink may be added to the ink according to the present invention. Specific examples include preservatives, antifungal agents, fragrances, and the like, and all of them can be used without any problems. . Examples of the preservative include "Proxel XL-2" (manufactured by Zeneca).
The addition amount is preferably in the range of 0 to 1%. As a fungicide, "Dencil P" (manufactured by Zeneca) can be exemplified.
About 1% is preferable.

The other remaining component of the ink may be water. However,
Dyes already mentioned (trade name "VERSATINT" Mill)
(Iken Chemical Co., Ltd.) is usually dealt with a 40% aqueous solution, so that it may not be necessary to particularly add water during production.

The ink of the present invention is prepared by first dissolving the dye in water (or, if necessary, diluting the solution if necessary), and stirring the fixing agent such as polyvinyl alcohol or polyvinylpyrrolidone so as not to cause mamako. Add little by little while dissolving completely. After the fixing agent is completely dissolved, it is manufactured by adding other additives and completely dissolving it.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. However, the present invention is not limited only to the examples.

(Example 1) Aqueous dye solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 1000, saponification degree: 89%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 81.1% Water 15.1% Polyvinyl alcohol 3.8%

Example 2 Aqueous dye solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 700, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 75.0% Water 20.0% Polyvinyl alcohol 5.0%

Example 3 Aqueous dye solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 700, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 67.0% Water 26.3% Polyvinyl alcohol 6.7%

Example 4 Aqueous dye solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 500, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 60.0% Water 32.0% Polyvinyl alcohol 8.0%

Example 5 An aqueous dye solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 95.0% Polyvinylpyrrolidone 5.0%

Example 6 Aqueous dye solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 92.0% Polyvinylpyrrolidone 8.0%

Example 7 Aqueous dye solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 90.0% Polyvinyl pyrrolidone 10.0%

Example 8 Aqueous dye solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 88.0% Polyvinylpyrrolidone 12.0%

(Comparative Example 1) Dye aqueous solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 500, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 85.7% Water 11.4% Polyvinyl alcohol 2.9%

(Comparative Example 2) Dye aqueous solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 500, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 50.0% Water 40.0% Polyvinyl alcohol 10.0%

(Comparative Example 3) Dye aqueous solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 96.5% Polyvinylpyrrolidone 3.5%

(Comparative Example 4) Dye aqueous solution (Mellike)
n Chemical's product name "PALER" 40%
Aqueous solution), polyvinyl pyrrolidone (molecular weight 4000)
0) was added little by little while stirring to prevent mamako and completely dissolved to obtain a black ink composition. Dye aqueous solution 85.0% Polyvinyl pyrrolidone 15.0%

Comparative Example 5 Aqueous Dye Solution (Melike
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 1500, saponification degree: 87%) was added little by little while stirring to prevent mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 75.0% Water 20.0% Polyvinyl alcohol 5.0%

(Comparative Example 6) Dye aqueous solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T "(40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 200, saponification degree: 87%) was added little by little while stirring so as not to form mamako, and completely dissolved to obtain a black ink composition. Dye aqueous solution 75.0% Water 20.0% Polyvinyl alcohol 5.0%

Comparative Example 7 Dye Aqueous Solution (Mellike)
Product name "VERSATIN" manufactured by n Chemical
T) (40% aqueous solution) was diluted with water, and polyvinyl alcohol (polymerization degree: 700, saponification degree: 80%) was added little by little while stirring so that mamako was not formed. However, the supernatant was not completely dissolved. Separately, a black ink composition was obtained. Dye aqueous solution 75.0% Water 20.0% Polyvinyl alcohol 5.0%

(Erasability Test) Using a water-free brush (No. 4 brush) on a cotton broad test cloth,
4 and the colorant compositions of Comparative Examples 1 to 4 were applied and left at room temperature until touch-drying. After drying, washing was carried out at 25 ° C. for 15 minutes using a synthetic detergent (adjusted to 0.2%) in a washing machine, followed by washing with water for 15 minutes. After drying, it was visually evaluated according to the following criteria. 4 or more passed as the erasable colorant composition. ◎ ・ ・ ・ ・ ・ ・ Completely erased.・ ・ ・: Almost erased. (It remains faintly when seen through the light.) × ····· Same as before washing.

(Bleeding Test) The ink compositions according to Examples and Comparative Examples were copied on a calligraphy paper using a brush and the bleeding was visually evaluated. ◎ ・ ・ ・ ・ ・ ・ No bleeding.・ ・ ・: Some bleeding was observed. ×: Bleeding as a whole.

(Viscosity) The viscosity at 20 ° C. was measured with an E-type viscometer. ◎ ・ ・ ・ ・ ・ ・ 25mpa · s or less.・ ・ ・: 25 to 45 mpa · s. X: 45 mpa · s or more.

(Concentration) A test paper coated undiluted on a screen paper (white Kent paper) and a test paper diluted with a water: black ink composition at a ratio of 2: 1 were prepared, each HVC was measured, and the difference in lightness was measured. Compared. A: Lightness difference of 1.5 or less.・ ・ ・: Lightness difference 1.5 to 2.5. ×: Lightness difference of 2.5 or more.

(Fixability) After copying on a calligraphy paper and drying, place a half paper on top and transfer weight (diameter 40 mm, weight 5
00g) was placed, and the state of transfer to the drawing paper at a speed of about 15 cm / s was visually evaluated. A: No transfer. ○: faint transfer. ×: Transfer completely.

Table 1 shows the results of the tests for each of the examples and comparative examples.

[0049]

[Table 1]

[0050]

The ink composition according to the present invention has excellent erasing properties and can be easily erased by washing even if it is accidentally attached to clothes or the like. Furthermore, it is excellent in various factors such as bleeding, transfer and density, and is excellent in brush character characteristics.

Claims (9)

[Claims] 1. A black ink composition containing an easily erasable colorant and water. 2. The ink composition according to claim 1, wherein the easily erasable colorant is a compound represented by the following general formula. Embedded image (However, R is a dye group, n is 15 or more, X is 1 to 16,
The product of n and X is 30 to 200) 3. The black ink composition according to claim 1, which contains an easily erasable colorant in an amount of 20 to 40% by weight. 4. The ink composition according to claim 1, further comprising a fixing agent. 5. The ink composition according to claim 4, wherein polyvinyl alcohol or polyvinylpyrrolidone is used as a fixing agent. 6. The ink composition according to claim 5, wherein the viscosity (20 ° C.) of a 4% aqueous solution of polyvinyl alcohol is 3.5 to 16.0 mPa · S or less. 7. The polymerization degree of the polyvinyl alcohol is 300.
The ink composition according to claim 5 or 6, wherein the saponification degree is from 87 to 89 mol%. 8. The ink composition according to claim 5, which contains 3 to 8% of polyvinyl alcohol. 9. The black ink composition according to claim 5, which contains 4 to 12% of polyvinylpyrrolidone.