JPS6049070A - Water-based ink - Google Patents

Abstract

PURPOSE:To provide a water-based ink free from the run and interruption of the recorded image when used as an ink-jet recording ink, and having excellent jet stability, by removing admixed surface active substance from a water-soluble direct dye or acidic dye with an adsorbent resin, and using the treated dye as a component. CONSTITUTION:A water-soluble direct dye or acidic dye is treated with an adsorbent resin composed of a phenolic resin having amine-type exchange group, a phenolic resin devoid of functional group, a styrene resin devoid of functional group, etc. to remove the surface active substance from the dye. At least one of the refined direct dye or acidic dye is used as a component of the objective water-based ink.

Description

[Detailed Description of the Invention] 1. The present invention also relates to a water-based ink for recorders, writing instruments, etc.
In particular, it relates to an aqueous ink suitable for inkjet recording.

Conventional technology Commercially available dyes often contain substances that exhibit surface activity, and when these are used as dyes in water-based inks, even if the amount of substances that exhibit surface activity contained in them is small, the surface tension of the ink will increase. This can reduce the amount of water and generate bubbles, which can cause blurring or sharpness in images. In addition, especially when used for inkjet recording, the decrease in surface tension and the deadness of bubbles have a negative effect on the jet GH stability and image qSI properties (1).

Conventionally, there is no technology that focuses on a substance exhibiting such surface activity, removes it from a dye, and uses it in an aqueous ink.

Purpose The purpose is to provide an aqueous ink that does not cause blurring or sharpness in images and has excellent jetting stability and image characteristics when used for inkjet recording.

Structure The present invention provides at least one of water-soluble direct dyes and acid dyes from which surface-active substances are removed using an adsorption resin.
The gist is a water-based ink that is characterized by its ability to bind seeds.

However, in accordance with the present invention, we have elucidated the adverse effects of surfactant substances in dyes used in water-based inks, and investigated the effective removal of these substances, and have found that compared to various anion exchange resins, We have found that resins classified as adsorption resins are effective. Such absorbing resins include 71-nol resins in which the exchange group is amine type, two-1-nol resins (1 fat, non-functional 7.B type), and the like.

These are, for example, product names 3-761, S-771, S-7.
62, S-861, and S-862 (all manufactured by Yukagakusha Co., Ltd.) are used.

To purify the dye using an adsorption resin, it is possible to treat the dye with an aqueous solution of only the dye before producing the ink, or to dissolve the dye in water and a wetting agent such as a polyhydric alcohol during the ink production. It is also possible to treat with adsorbed A4 fat at that point.

Further, the VJ manufacturing method can also be performed by badge processing or by a method in which ink is developed in a column of resin.

Hereinafter, a specific example will be described in which the present invention is applied to Infusiera 1-recording ink.

Example 1 An exchangeable J-Yamine type phenolic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: E'S-771) as an adsorption resin was washed with water, converted to -o + + with sodium hydroxide, and further washed with water.

Separately, 100 g of a 10 wt % aqueous solution of C, 1, AR2139 (manufactured by Daiwa Kasei Co., Ltd.) as a dye was prepared, 300 g of the absorbent resin was added thereto, and the mixture was left overnight. It is then filtered to remove the resin and dried to remove the purified dye.

When 2 wt% aqueous solutions of each of the purified dye and the unpurified dye were prepared and the surface tension was measured, the purified product was approximately 606 yne.
/ cm, while the unrefined product is approximately 50 dyne
/air, a surface protein increase of 10 dync/cm was observed upon purification. In addition, the amount of bubbles generated was reduced, and the bubble disappearance time was also shortened by more than 10 times.

Using the dye purified above, an inkjet recording ink was prepared according to the following formulation.

vJ dyeing agent 3wt% diethylene glycol 22.5wt% glycol ?
,! iwt% Preservative and anti-mold agent (product name PULLTOP 33, manufactured by Narita Pharmaceutical)
0.3wt% ion exchange water 6G, 7wt% The surface tension of this ink was 4Gdyne/Ca11. The surface tension of unrefined dye is 40 dync/c
It was m. In addition, the generation of bubbles was greatly reduced, and the half-life of bubbles was reduced to about 1/10.

When inkjet recording was performed using this ink, there was no disturbance of the droplets due to bubbles during ejection, nor was there any instability in ejection due to clogging. Bubbles were generated in the gutter or ink tank, and the bubbles caused turbulence in the droplets during ejection.

Example 2 A styrene matrix, structure MP, and non-functional fume-type adsorption resin (trade name 3-861, manufactured by Sumitomo Chemical Co., Ltd.) were treated in the same manner as in Example 1 to produce dyes UC and I.

It was used for purification of AR289. When a test was conducted using the same method as in Example 1, good results similar to those in Example 1 were obtained.

Example 3 Acrylic matrix, composition %i M P , exchanged lipolyamine type adsorption resin (trade name KA-850, manufactured by Sumitomo Chemical Co., Ltd.)
was treated in the same manner as in Example 1, and the dye was added to C,[,AR1
43 (Hiki Kagakusha!XI). When a test was conducted in the same manner as in Example 1, good results similar to those in Example were obtained.

Example 4 Phenolic adsorption resin with amino type exchange group (product name E
S-771 (manufactured by Sumitomo Chemical Co., Ltd.) was treated in the same manner as in Example 1, and used as a dye to purify Direct Black 154 (manufactured by Odugaya Chemical Co., Ltd.). When tested in the same manner as in Example 1, good results similar to those in Example 1 were obtained.
Renoko.

Example 5 Dye C11°AR289 used in Example 1
The ink was created using the same absorbent resin as in Example 4!l!!l!l!
Shita. After filtration with a filter, Infusiella 1~ was used for recording, no disturbance caused by bubbles in injection 11.1 occurred, the surface tension increased, and a good r'tK+++V test result was obtained.

Effects As explained above, the ink of the present invention, when used for Infusiera 1 to other recording and writing purposes, does not cause blurring or sharpness of lines and has excellent jetting stability.

! 14i Applicant Ricoh Co., Ltd. - Agent Patent Attorney Hide Komatsu Agent Patent Attorney Hiroshi Asahi

Claims (2)

[Claims] (1) Water-based ink characterized by containing water-soluble direct dye J3 from which surface-active substances are removed with an adsorbent resin and one type of acid dye. . (2) The water (4+ ink) according to claim 1, in which the adsorption resin is a phenolic resin with an amine type exchange group, a styrene resin with a non-functional group type, or a hydroxy type phenolic resin.