JPH0745639B2 - Ink composition - Google Patents

Description

TECHNICAL FIELD The present invention is an ink composition for inkjet, particularly an ink composition containing a cyan dye, and is also used as a writing instrument, a recorder, a stamp and other printing inks.

[Prior Art] The properties required as an inkjet dye are: 1) Good solubility stability in ink components.

2) The printed image is excellent in water resistance and light resistance.

3) The printed image has no bleeding and the ink dries quickly.

4) The ink is safe.

Etc.

Phthalocyanine is widely used as a cyan dye because of its good color tone and light resistance.

However, those having a sulfone group introduced to increase the water solubility of phthalocyanine have a drawback that the water resistance is poor even when printed on paper.

Those having a carboxylic acid group introduced therein are dissociated in the ink at high pH, but protons are added at neutral pH or low pH (7 to 4), and the solubility tends to decrease.

CI direct blue 1, 8, 86, 87 and CI acid blue 1, 7, 249, etc. are conventionally known as various cyan dyes, but CI acid blue has poor solubility and CI acid blue is There was a problem of poor water resistance.

Further, as an invention aimed at improving water resistance, JP-A-61-27
There are 72 etc., but none have been found that simultaneously satisfy solubility and water resistance.

[Object] The present invention is intended to solve the above-mentioned problems of the prior art, and is an ink that can improve water resistance of an image, wettability of an ink, and prevent bleeding of an image. The purpose is to provide a composition.

[Structure] The structure of the present invention for achieving the above object is an ink composition containing a dye represented by the following general formula.

General formula (However, in the symbols of the above general formula, CuPc is copper phthalocyanine R ₁ , R ₂ is hydrogen, a lower alkyl group, a hydroxyalkyl group, M ⁺ is a hydrogen cation, an alkali metal cation, an ammonium ion, an organic ammonium ion, m, n is an integer of 0 to 4, and m + n = 4.) Since the charge control type inkjet printer uses a metal material for the nozzle, the liquidity of the ink is kept alkaline. On the other hand, the dye of the present invention in which a carboxylic acid group is added to phthalocyanine to improve the solubility in water is stable in an alkaline (pH 8 to 12) ink, but it is commercially available (mostly acidic paper). ), The solubility in water decreases.

That is, although the dye of the present invention has excellent solubility in ink, it results in excellent water resistance after printing. In addition, the image using the dye of the present invention has the advantages that there is little bleeding on plain paper, the dot shape is close to a perfect circle, and the drying property is excellent.

Specific examples of the dyes of the present invention include those shown in Table 1 below. That is, the symbols in the general formulas described in the claims are specifically shown in the table.

Illustrating the method for synthesizing the dye of the present invention, first, copper phthalocyanine tetracarboxylic acid is prepared by a known method [for example, Macromo
L. Chem. 181, 575 (1980)].

Next, in benzene, a part of the above-mentioned carboxyl group is converted to cambonic acid chloride by thionyl chloride. Further, an alkylamine and a hydroxylamine are reacted to synthesize the dye of the present invention.

For example, the compound No. 1 in Table 1 above (formally named 29H, 31H
−Phthalocyanine−2,9,16,23−tetracarboxylic acid c
opper complex) is known (eg J.Chim.Phys.Phy
s.Chim.Biol.1979; 571-573). In this invention Macromol.
Chem. 181, 575 (1980) (this is an iron complex etc., but there is no copper), and was synthesized.

Trimellitic anhydride 0.1 mol Urea 1 mol Cupric chloride 0.06 mol Ammonium molybdate 0.002 mol The above mixture is reacted in 300 cc nitrobenzene at 160 ° C for 3 hours and washed with methanol to obtain 600 cc of water.
0.5 mol of NaOH was added thereto, and the mixture was heated and refluxed to obtain the desired substance.

Similarly, the compounds of Nos. 2 to 6 are the same as the above compounds in pyridine.
-COOH is heated to -COOH by heating with double molar amount of thionyl chloride.
After being made C1, it was reacted with the corresponding amine (diethanolamine in the case of No. 2) to obtain the target substance.

The number of substitutions was changed by changing the amount of thionyl chloride or changing the amount of amine.

The counter cation (M ^{+ in} Table 1) was introduced by adding the corresponding alkali metal hydroxide or amine after acid precipitation of the above material.

Nos. 7 to 9 can be prepared in the same manner as Nos. _{2 to 6,} but they are intermediates of No. 1 synthesis, and if the amount of NaOH is too small or the perfusion time is short, some -CONH ₂ remains. This is also considered to be effective in reducing the solubility and improving the water resistance.

As the ink component of the present invention, conventionally known ink components, that is, various wetting agents, antiseptic agents, antifungal agents, pH adjusters and the like are used in addition to the above dyes.

The composition of the ink composition of the present invention and the test results thereof are specifically shown in Table 2 below by Examples. The remaining weight percent in the soup stock ink composition is water.

The ink composition was tested according to the following method.

As the printer, a charge control type inkjet printer with a nozzle diameter of 30 μm was used.

Jet stability: The number of days that can be normally printed without causing nozzle clogging after printing is stopped.

Water resistance: The main color density fading rate (%) when printed on commercially available paper and immersed in water at 30 ° C. for 1 minute.

Drying time: The time (sec) at which the image does not transfer to the filter paper even if the image is brought into contact with a commercially available filter paper after printing.

Bleeding, dot shape ○: The shape of the dot is close to a perfect circle and there is no bleeding.

Δ: Some bleeding is seen.

X: A large amount of bleeding occurs.

The dyes used in Comparative Examples 1 to 3 are as follows.

No.10A.Blue 249 No.11D.Blue 87 No.12D.Blue 86 [Effect] As described above, the ink composition of the present invention is excellent in ink jetting stability, the ink dries quickly when printed at the same time, there is no bleeding of dots, and the water resistance of an image is high. It has a remarkable effect of being excellent.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroyuki Uemura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Nobufumi Nagai 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (1)

[Claims] 1. An ink composition comprising a dye represented by the following general formula. General formula (However, in the above general formula, CuPc is copper phthalocyanine R ₁ and R ₂ is hydrogen, a lower alkyl group, a hydroxyalkyl group, M ⁺ is a hydrogen cation, an alkali metal cation, an ammonium ion, an organic ammonium ion, m, n Are each an integer of 0 to 4 and m + n = 4.)