JP3354680B2 - Aqueous ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink composition used for writing instruments such as ball-point pens, felt-tip pens, and line markers, and for plotters, recorder pens and the like. The present invention relates to a water-based ink composition having good cap-off properties, very little discoloration even when writing on thermal paper, and excellent writing characteristics.

[0002]

2. Description of the Related Art A dye ink composition is known as a water-based ink composition used in conventional writing instruments such as ballpoint pens, felt-tip pens, line markers, etc., plotters, recorder pens and the like. In addition, the light resistance was poor, the handwriting was discolored when writing on thermal paper, and the handwriting was liable to bleed. Japanese Patent Application Laid-Open No. 61-26 discloses a solution to this problem.
JP-A-8775 and JP-A-4-7367 disclose a mixed polymer comprising a cyano group-containing vinyl monomer, a vinyl monomer such as methacrylic acid and acrylic acid, and a vinyl monomer such as methyl methacrylate. Discloses a fluorescent ink colored with a fluorescent dye. However, the composition had problems in resistance to discoloration, bleeding and cap-off of writing on thermal paper.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an emulsion polymer obtained by emulsion polymerization of a mixture of acrylonitrile and methacrylic acid or acrylic acid and methyl methacrylate and / or ethyl methacrylate with a dye and / or a pigment. By adding an appropriate amount of glycerin in an aqueous ink composition using a colored coloring material, water resistance, light resistance, bleeding resistance, and cap-off resistance are good, and discoloration may occur even when written on thermal paper. It is an object of the present invention to obtain an aqueous ink composition having extremely few features and good writing characteristics.

[0004]

In the present invention, as a result of intensive studies in view of the above-mentioned conventional problems, the above object can be achieved by specifying the amount of acrylonitrile and the type and amount of the hydrophilic organic solvent. I found that.

That is, the aqueous ink composition of the present invention comprises:
5 to 60% by weight of acrylonitrile and methacrylic acid or
Acrylic acid 0 . 5 to 20% by weight, and methyl (meth) acrylate and / or ethyl (meth) acrylate 20
An emulsion polymer obtained by emulsion polymerization of a mixture consisting of ９４94.5% by weight is colored with a dye and / or a pigment.
An aqueous ink composition comprising at least 50% by weight, and the others mainly consisting of water.

In the above, acrylonitrile can be used in an amount of 5 to 60% by weight in the emulsion polymer composition.
~ 40% by weight is preferred. If it exceeds 60% by weight, emulsion polymerization becomes difficult and storage stability decreases,
The viscosity of the resulting ink composition is increased to deteriorate ink flowability, writing characteristics, etc., and if it is less than 5% by weight, color clarity, water resistance and sunlight fastness are reduced. On the other hand, methacrylic acid
Or acrylic acid is the coloring and sharpness of dyes and pigments
It is used as a component for improving the degree. The meta
The amount of crylic acid or acrylic acid used is 0.1% in the monomer mixture.
5 to 20% by weight can be used, and 10 to 18% by weight is preferable. When the amount is more than 20% by weight, emulsion polymerization is difficult. When the amount is less than 0.5% by weight, sharpness and water resistance are lowered, and a high-concentration color ink composition cannot be obtained. On the other hand, methyl (meth) acrylate and / or ethyl (meth)
Acrylate is used as the skeleton of the emulsion polymer, and is preferably methyl (meth) acrylate alone.
It is also preferable to use a combination of methyl (meth) acrylate and ethyl (meth) acrylate. The amount of the methyl (meth) acrylate and / or ethyl (meth) acrylate used may be 20 to 94.5% by weight in the monomer mixture,
50-85% by weight is preferred. If it exceeds 94.5% by weight, the fastness to sunlight decreases, and if it is less than 20% by weight, emulsion polymerization becomes difficult and storage stability also decreases.

In the method for producing the emulsion polymer, an activator such as sodium dodecylbenzenesulfonate and an initiator such as potassium persulfate and ammonium persulfate are dissolved in ion-exchanged water.
The mixture is charged into a four-necked flask or the like, and then the above-mentioned monomer is added dropwise. The mixture is heated to 80 ° C., stirred for 3 hours, cooled to room temperature and filtered to obtain an emulsion of the emulsion polymer. However, the emulsion polymer used in the present invention is not limited to the above-mentioned production method, and the obtained emulsion polymer may have the above-mentioned composition.

As the dyes and pigments for coloring the emulsion polymer, general dyes and pigments can be used. Specifically, when represented by a color index number (CI), BASI
C YELLOW 1,2,11,28,35,36,
40,50, BASIC ORENGE 2,14,1
5, 21, 22, 30, 32, 33, 34, BASIC
RED 1,2,9,12,13,14,15,1
7, 18, 22, 23, 24, 27, 29, 32, 3
4,35,36,37,38,39,40, BASIC
VIOLET 1,3,7,10,14,15,1
6, 21, 25, 26, 27, 28, BASIC BL
UE 1,3,5,7,9,19,21,22,24,
25, 26, 28, 29, 40, 41, 44, 45, 4
7, 54, 58, 59, 60, 64, 65, 66, 6
7, 68, 93, BASIC GREEN 1, 4,
6, BASIC BROWN 1,11,12, BAS
IC BLACK 2,8, ACID YELLOW
3,7, ACID RED 52,77,87,92,
ACID BLUE 9, DISPERSE YELL
OW 5,64,82,12, DISPERSE OR
ENGE 11, 13, 29, 73, DISPERSE
RED 54, 58, 60, 88, 92, 127, D
ISPERSE BLUE 7,56,60,73,8
1,91, DIRECT YELLOW 12,44,
85, 142, DIRECT ORENGE 8, 2
6,79,83,89, DIRECT RED 4,
9,23,31,81, DIRECT BLUE 2
2,71,78,86,90,89, DIRECT G
REEN 6,59,80, FLUORESCENT
BRIGTENING AGENT 55, FLUO
RESCENT BRIGHTENING WHITE
X WS 52, FLUORESCENT 112, 1
62, SOLVENT YELLOW 25, 33, 4
4,93,116, SOLVENT RED 49,8
2,83,84,111,146, SOLVENT B
LUE 5,35,83, SOLVENT GREEN
3,7, PIGMENT YELLOW 1,14
7, PIGMENT RED 53, 57, 249, 2
50, 251, PIGMENT GREEN 7, PI
GMENT BLUE 15, and the like. However, it is not limited to these dyes and pigments. The amount of the dye and / or pigment used can be 0.01 to 20% by weight, preferably 0.1 to 15% by weight, based on 100 parts by weight of the solid content of the emulsion polymer. When the amount exceeds 20% by weight, the emulsion polymer and unbound dye and / or
Or the pigment increases, the water resistance of the ink composition decreases,
When the content is less than 0.01% by weight, the coloring becomes light.

As a method for producing the colored product, the dye and / or pigment is dispersed in an aqueous solution of an anionic activator such as sodium dodecylbenzenesulfonate, sodium POE alkyl ether sulfate or sodium alkyldiphenyl ether disulfonate. The above emulsion polymer is added with an anionic surfactant or a nonionic surfactant as needed, and
After heating to 0 ° C. and stirring for 1 hour, the mixture is cooled to room temperature and filtered to obtain an emulsion of the colored body.

The method for converting the aqueous ink composition of the present invention into an ink can be achieved by mixing one or more of the above-mentioned colored emulsions with glycerin, ion-exchanged water, a preservative and the like and stirring for one hour. A water-based ink composition is obtained, but the amount of the colored body used is 2 to 4
0% by weight (as solids), preferably 3 to 2%
8% by weight can be used. If it exceeds 40% by weight, the viscosity becomes high and the writability decreases, and if it is less than 2% by weight, the color becomes light.

The amount of glycerin used is 2 in the total ink composition.
0-60% by weight can be used, preferably 20-50% by weight
Can be used. When the content exceeds 60% by weight, drying of the handwriting becomes slow and bleeding becomes severe, and when it is less than 20% by weight, drying of the pen tip becomes fast. In addition, emulsion polymer emulsion,
The colored emulsion and the ink composition naturally contain an appropriate amount of water necessary for dispersing the components. Further, in the formation of the ink, if necessary, commonly used additives such as a preservative, a fungicide, an antifoaming agent, an ultraviolet absorber, and a surfactant may be used.

[0012]

According to the present invention, a dye and / or
Or because it is an emulsion aqueous ink composition comprising a colored body emulsion colored with a pigment and the glycerin, water resistance, light resistance, bleeding resistance, cap-off resistance, and discoloration even when written on thermal paper. It has the effect of extremely low writing characteristics.

[0013]

The present invention will be described in more detail with reference to the following examples. Examples 1 and 2 are shown in [Table 1].

[Table 1]

Further, Comparative Examples 1 to 3 are shown in [Table 2].

[Table 2]

Further, Examples 1 and 2 and Comparative Examples 1 to 3
Each of the inks was tested for water resistance, light resistance, bleeding resistance, cap-off resistance, heat-sensitive paper resistance, and stenographic ink. The results are shown in [Table 3] and [Table 4].

[Table 3]

[0016]

[Table 4]

The test method and evaluation method at this time are shown below. Test method Water resistance: After writing for 1 minute on writing paper, the handwriting is immersed in still water for 1 hour, and then air-dried. Lightfastness: Irradiate the paper written on the writing paper with a fade meter for 2 hours. Bleeding resistance: The pen point is left on the writing paper with a load of 100 g for 10 seconds. Cap-off resistance: Remove the cap of the writing instrument and leave it at 25 ° C.
After being left in a 65% constant temperature chamber for 2 hours, five 12 cm wide lines are drawn on the square chip line marker, and 10 continuous circles of 12 cm width are drawn on the round chip line marker. Heat-resistant paper: Write on FAX paper and leave for 24 hours. Shorthand: Write five continuous lines of ─10 cm / s. Evaluation method Water resistance 耐 Discoloration degree is visually determined. Lightfastness─ Measure color with blue scale. Bleeding resistance: The bleeding method and the back bleed were visually observed, and the number of missing papers was counted. Cap-off resistance ─ Check the distance until you can write normally. Thermal paper resistance: The degree of discoloration is visually determined. Shorthand: Visually determine how thin. From the above results, the aqueous ink composition of the present invention has water resistance, light resistance, bleeding resistance, cap-off resistance, heat resistance,
It turns out that it is excellent in writing characteristics, such as shorthand writing.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (1)

(57) [Claims] 1. A acrylonitrile 5% to 60% by weight, meta
An emulsion polymer obtained by emulsion polymerization of a mixture consisting of 0.5 to 20% by weight of acrylic acid or acrylic acid and 20 to 94.5% by weight of methyl (meth) acrylate and / or ethyl (meth) acrylate is dye and An aqueous ink composition comprising at least 10 to 80% by weight of a colored body colored with a pigment and / or 20 to 50% by weight of glycerin in the ink composition.