JPH0751688B2 - Method for producing ink for ink-jet printing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an ink for ink-jet printing. More specifically, it relates to a method for producing an ink for ink jet printing of a disperse dye.

(Prior Art and Problems) Conventionally, as an ink for ink jet printing of a disperse dye, a dissolution type in which a disperse dye is dissolved in an organic solvent (JP-A-50-59108) or a commercially available dispersion in water A dispersion type in which a dye is easily dispersed (JP-A-54-18974) has been proposed.

However, the dissolution type ink has a low solubility of the disperse dye and it is difficult to produce a high concentration ink, and the dispersion type ink can secure a practical dye concentration, but the dispersion stability has not been sufficiently solved.

(Means for Solving Problems) An object of the present invention is to produce an ink jet printing ink of a disperse dye which has a sharp particle size distribution and is excellent in long-term dispersion stability, continuous ejection stability, and the like. It was achieved as a result of the examination as a result, and its gist is to perform a mechanical dispersion treatment of a disperse dye and water in the presence of a dispersant to obtain a particle diameter of 0.05 to 0.3 μm.
A method for producing an ink for ink-jet printing, comprising a dispersion having a viscosity of 1 to 20 centipoise containing disperse dye particles, and then removing a solid content settling by centrifugal separation under a centrifugal force of 500 to 2000 G. Exist in.

The present invention will be described in detail below.

Examples of the disperse dye used in the present invention include well-known disperse dyes such as anthraquinone-based, azo-based, quinophthalone-based, methine-based, and hetero-condensed ring-based, which are insoluble or hardly soluble in water.

For example, green dyes such as pyridone dyes, pyrazolone dyes, quinophthalone dyes, methine dyes, and azo dyes are used as yellow dyes, and anthraquinone dyes, azo dyes, heteroazo dyes, and methine dyes are used as red dyes. As a bluish dye, a blue dye such as anthraquinone dye, naphthoquinone dye, or heteroazo dye is preferably used.

Further, it is possible to use a so-called natural color full color composed of four colors including a combination of these three primary colors and a black color obtained from these three primary colors.

The disperse dye is usually used in an amount of 1 to 30% by weight, particularly 3 to 15% by weight, based on the total amount of the ink. The main dispersion medium of the ink of the present invention is water, and an aqueous dispersion medium obtained by adding a dispersant and a desired auxiliary agent to this is used. An appropriate amount of water is usually about 40 to 85% by weight of the total amount of ink.

As the dispersant, various nonionic surfactants, anionic surfactants and cationic surfactants which are conventionally known as dispersants for disperse dyes can be widely used.
Further, in addition to the dispersant, auxiliary agents such as ethylene glycol and ethylene glycol monomethyl ether, such as anti-drying agents, silicon-based defoaming agents, and dissolution accelerators can be appropriately used in combination. Is usually used in the range of 10 to 50% by weight with respect to the total amount of ink.

In the method of the present invention, first, a disperse dye and water are mechanically dispersed in the presence of a dispersant to uniformly disperse them.

In the dispersion treatment, the particle size of most of the disperse dye particles in the dispersion liquid is
It is necessary to carry out mechanical treatment until it becomes 0.05 to 0.3 μm, preferably 0.05 to 0.2 μm, and the viscosity of the dispersion becomes 1 to 20 centipoises (cps), preferably 1 to 15 centipoises. For the dispersion treatment, a sand glider, an attritor, a permill, etc. are used, and particularly when a sound glider is used, preferable results can be obtained.

The dispersion liquid subjected to the dispersion treatment is then subjected to a centrifugal force of 500 to 2000 G,
Preferably, the target ink is obtained by centrifuging under a centrifugal force of 1000 to 1500 G and removing solid particles such as coarse particles of disperse dye (specific gravity of about 1.1 to 1.5), contaminants from equipment, and impurities. Is obtained. As the centrifugal separator used at this time, a vertical or horizontal continuous type is used.

Note that G in the above means a centrifugal effect, which is a dimensionless number indicating the magnitude of centrifugal force, and indicates the centrifugal force and gravity that act on a mass point that is rotating.

(Effect of the Invention) According to the method of the present invention, it is possible to obtain an ink jet printing ink of a disperse dye, which has extremely excellent dispersion stability during long-term storage and ejection stability during use.

EXAMPLES Next, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.

The test methods in Examples and Comparative Examples are as follows.

(1) Inking method An ink was made into ink as follows using an Aniler type sand grinder manufactured by Go Arashi Seisakusho.

Ink Composition A disperse dye cake, a dispersant, an anti-drying agent, an antifoaming agent and water were mixed and the following dispersion treatment was carried out.

Dispersion treatment With an Aniler type sand grinder, glass bead diameter
The disk rotation speed was 2000 rpm using 0.1 to 0.5 mm. The target main grain size was 0.3 μm or less.

(2) Centrifugation treatment Centrifugation was performed using a H-600 type continuous centrifuge manufactured by Domestic Centrifuge Co., Ltd., and the ink of (1) above was subjected to a centrifugal force of 1200 G and a processing speed of 1,000 ml / hr. Ivy. Target main particle size is 0.3μ
It was set to m or less. In the comparative example, the ink was only pressurized by using viscous paper No. 60 manufactured by Toyo Paper Co., Ltd., and the centrifugal separation treatment was not performed.

(3) Ink physical property measuring method The ink obtained in (2) above was evaluated based on the following various ink physical property measuring methods.

Viscosity (centipoise) The viscosity of the ink was measured under the following conditions using a BL type viscometer manufactured by Tokyo Keiki Co., Ltd.

Measurement temperature: 25 ° C. Rotor used: No. 1 Rotor speed: 60 rpm Grain size Grain size was measured using the following equipment.

Particle size analyzer: Submicron particle analyzer N-4
(Manufactured by Coulter Inc.) Measurement particle size range: 0.003 to 3 μm Dispersion rate The ink was transferred to a 100 ml graduated cylinder and allowed to stand at room temperature for 7 days, and then 10 ml was withdrawn from the upper part and 10 ml from the lower part.

The absorbance at λmax of the sampled aqueous dye solution is measured. Then, the water dispersion rate was calculated by the following formula.

Discharge stability Using a commercially available on-demand type ink jet device, the ink was fed into a nozzle having a diameter of 100 μm at a rate of 3.5 ml / hr, and the state of continuous discharge for 24 hours was evaluated. In particular, the reliability of ejection was evaluated in terms of nozzle clogging.

Examples 1 and 2 and Comparative Examples 1 and 2 Inks were prepared from the mixtures having the following compositions by the above methods (1) and (2).

Composition Dye [the following formula (A) or (B)] 100 g Nonionic surfactant [a mixture of the following formulas (C) and (D)]
20 g anionic surfactant lignosulfonate [Reax85A Note 1] 10 g ethylene glycol 200 g silicon antifoaming agent [Shinetsu Silicone KS502 Note 2] 0.1g Water balance Total 1.000 g Note 1: Westraco Ltd. Note 2: Shin-Etsu Chemical Co., Ltd. Dye A: A quinophthalone disperse dye (powder) represented by the following structural formula.

Dye B: Anthraquinone-based disperse dye (powder) represented by the following structural formula.

Nonionic surfactant: As a result of examining various physical properties of the ink using the above-obtained ink according to the method of (3) above, as shown in Table 1, any of the inks for ink-jet printing manufactured according to the present invention is It was good.

Claims (2)

[Claims] 1. A disperse dye and water are mechanically dispersed in the presence of a dispersant to give a dispersion containing 1 to 20 centipoise of viscosity containing disperse dye particles having a particle size of 0.05 to 0.3 .mu.m, and then 500.
A method for producing an ink-jet printing ink, which comprises centrifuging under a centrifugal force of up to 2000 G to remove solids that settle. 2. The method for producing an ink for ink jet textile printing according to claim 1, wherein the mechanical dispersion treatment is a treatment with a sand grinder.