JP2737833B2 - Fluorescent ink composition for jet printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent ink composition for jet printing containing a fluorescent dye, and more particularly to a fluorescent ink composition for jet printing capable of obtaining a printed material having an image having high fluorescence. .

[0002]

2. Description of the Related Art An ink jet printer discharges an ink composition containing a fluorescent dye onto the surface of a printing medium,
Printing, graphics,
The fluorescent ink composition for jet printing used to form an image such as a line is described in, for example, JP-B-62-5079, JP-B-62-24024, and JP-A-6-500590, and is known. It is.

[0003]

However, these fluorescent ink compositions for jet printing can form an image of high fluorescence emission on the surface of a printing material having no liquid absorbing property. For example, when printing on an ink-jet printer, the fluorescent dye in the ink composition permeates and diffuses into the deep part of the printing material together with the solvent when printing on an ink-receiving printing material surface such as paper or fabric. It is operationally or economically difficult to increase the concentration of the fluorescent dye on the surface, which causes a problem that the fluorescence emission intensity on the surface of the printing medium is insufficient. In particular, when the liquid-absorptive printing material is colored with black or the like, there is a problem that the shortage of the fluorescence emission intensity on the surface of the printing material is remarkable.

The present invention solves the problems of the conventional fluorescent ink composition for jet printing, in which a larger amount of the fluorescent dye remains on the surface of the printing medium so that the amount of the fluorescent dye is reduced. It is an object of the present invention to provide a fluorescent ink composition for jet printing which can increase the concentration of a fluorescent dye and form an image with high fluorescence emission intensity.

[0005]

Means for Solving the Problems As a result of various studies for solving the above problems, the present inventors have found that transparent solid fine particles , particularly the features described below, are contained in the fluorescent ink composition for jet printing.
By including certain transparent solid fine particles , these fine particles adhere to the surface without penetrating deep into the printing medium, and the fluorescent dye is added to the ink composition before jet printing (that is, in the ink composition before application). Or, during jet printing (ie, when the ink composition is applied to the surface of the printing medium and penetrates into the deep part of the printing medium), the fine particles are adsorbed on the surface of the printing medium, so that penetration into the deep part of the printing medium is reduced. As a result, the inventors have found that the concentration of the fluorescent dye on the surface of the printing medium is increased, and an image having a high fluorescence emission intensity is obtained, thereby completing the present invention.

Namely, the present invention comprises a fluorescent dye, and in jet printing fluorescent ink composition containing water as a solvent, acrylic acid N- methoxymethyl nylon, meta
Graph of crylic acid or N-methylol acrylamide
Water-dispersible nylon resin and water-dispersible egg white-
Provided is a fluorescent ink composition for jet printing, comprising transparent solid fine particles having a particle size of 1 μm or less selected from the group consisting of chitosan reactants .

Hereinafter, the present invention will be described specifically. The fluorescent ink composition for jet printing of the present invention contains a fluorescent dye, transparent solid fine particles and water as a solvent as essential components, and may further contain a hydrophilic organic solvent, a water-soluble resin and various additives as necessary. it can.

The fluorescent dye used in the present invention is a fluorescent dye which emits fluorescence by various kinds of light such as ultraviolet light, infrared light or visible light, and can be appropriately selected according to the purpose of use. For example, in the case where fluorescent light is not emitted with visible light, but it is desired to emit fluorescent light when irradiated with infrared light, a fluorescent dye suitable for this may be appropriately selected. Specific examples of the fluorescent dye include CI Fluorescent Brightening Agent 14,
24, 30, 32, 52, 54, 69, 79, 84, 8
5, 86, 87, 90, 104, 112, 113, 11
4, 119, 121, 134, 135, 152, 16
6, 167, 168, 169, 191, 192, 20
1, 204, 214, 216, 217, 218, 22
3, 226, 229, 234, 236, 239, 24
0, 242, 257, 260, 271, 290, 31
0, 311, 312, 313, 314, 315; CI
Basic Red 1, 1-1; CI Basic Violet 10, 1
1: 1; CI Basic Yellow 35, 40, 95; CI
Basic Blue 7; P-quarterphenyl; P-terphenyl; 2,5-diphenyloxazole; 2- (1-
Naphthyl) -5-phenyloxazole; 2-phenyl-5- (4-biphenyl) -1,3,4-oxadiazole; 3-phenyl-7- (1,2-2H-naphthotriazolyl) -coumarin 3,7-bis (diethylamino) phenoxazonium nitrate; 3,7-bis (diethylamino) phenoxazonium nitrate; laser dyes DTTCI, DNTTCI, HDITCI;
IR-125, 132, 140, HIDC Iodide and the like are typical examples. Considering the storage stability of the fluorescent ink composition for jet printing, it is desirable that these fluorescent dyes be dissolved or stably dispersed in water. However, even hydrophobic dyes are used by adsorbing them to transparent solid fine particles in advance. It is possible.

The transparent solid fine particles used in the present invention are blended in order to increase the concentration of the fluorescent dye on the surface of the printing medium and to obtain an image having a high fluorescence emission intensity. That is, in the case of a liquid-absorbing printing material, the fluorescent dye easily penetrates and diffuses into the deep portion of the printing material together with the solvent, but when transparent solid fine particles are blended in the fluorescent ink composition for jet printing, these fine particles are used. Remains on the surface without penetrating into the deep part of the printing medium, and the fine particles remaining on the surface of the printing medium adsorb the fluorescent dye before or during jet printing, and the fluorescent dye is absorbed into the deep part of the printing medium. The penetration is suppressed, and as a result, the concentration of the fluorescent dye on the surface of the printing medium is increased.

The term "transparent" used in the present invention for transparent solid fine particles includes not only completely transparent but also colored or turbid as long as it transmits light. However, those which do not transmit light are unsuitable for the present invention because the fluorescence emission intensity is reduced and the printed material is stained. The particle diameter of the transparent solid fine particles is preferably 1 μm or less so as not to cause nozzle clogging of a jet printer, and also preferably 0.01 to 0 in consideration of the fact that the particles tend to remain on the surface of the printing medium. 0.5 μm .

[0011] Examples of such a transparent solid particulates, not only have a stable water-dispersible, have good dyeing property by the fluorescent dye the N - methoxymethylated nylon (meth) acrylate or N- methylol acrylamide 20 to 40
Weight-% grafted water-dispersible nylon resin [commercially available products: Toresin FS-350, Toresin FS-500
(Each is manufactured by Teikoku Chemical Industry Co., Ltd.)] and water obtained by adjusting the pH of the diluted egg white water to 3 to 4 with an acid, adding chitosan and an aldehyde-based cross-linking agent, causing a heat reaction, and then adjusting the pH to about 5 with an alkali. Dispersible egg white-chitosan reactants are particularly preferred.

The solvent used in the present invention is water, preferably distilled water or ion-exchanged water, and if necessary, methyl alcohol, ethyl alcohol, isopropyl alcohol, dioxane, acetone, methyl ethyl ketone, carbitol, dimethyl sulfoxide. It is also possible to partially use a water-miscible organic solvent such as

The ink composition of the present invention contains the above-described components as essential components, and the mixing ratio of the fluorescent dye is 0.001 to 10% by weight, preferably 0.005 to 2% by weight. It is suitable that the transparent solid fine particles are 2 to 45% by weight, preferably 3 to 35% by weight, and the solvent is 50% by weight or more.

The ink composition of the present invention may further comprise a polyacrylic resin, as necessary, so that transparent solid fine particles are firmly adhered to the surface of the printing medium and fine particles adhered to the nozzle of the jet printer can be easily removed. 1 to 45% by weight of a water-soluble resin such as acid, polyacrylate, styrene-maleic acid copolymer, styrenesulfonic acid-maleic acid copolymer, polyester, hydroxyethylcellulose, polyvinyl alcohol, maltosyl cyclodextrin, and polyethylene glycol %; Lithium nitrate, lithium nitrite, ammonium sulfite, ammonium formate, ammonium acetate, lithium halide, sodium thiocyanate, etc., conductivity modifiers, dispersants such as amine-modified silicone dispersants, preservatives etc. Additives should be contained in an amount of 0.1 to 5% by weight. Can.

The ink composition of the present invention needs to have characteristics suitable for printing by an ink jet printer. Therefore, the ink composition has a viscosity of about 1 to 10 mP.
a · sec (20 ° C), specific resistance is about 50-3000Ω ·
cm, specific gravity about 0.8-1.2, surface tension about 20-6
It is desirable to be in the range of 0 dynes / cm.

In the ink composition of the present invention, all the components are mixed and stirred at once, or a fluorescent dye, transparent solid fine particles and a part of a solvent are mixed and stirred in advance, and the fluorescent dye is adsorbed on the fine particles. And the remaining components are mixed and stirred, and then filtered and purified with a filter having a pore size of about 1/10 or less of the nozzle diameter of the inkjet printer to be used.

As the ink jet printer which can perform jet printing using the ink composition of the present invention, conventionally known various printers can be used. Specifically, a charge control system, an ink on demand system, a thermal A typical example is a method in which an ink composition is ejected by a head.

[0018]

The present invention will be described below in detail with reference to examples and comparative examples. In the Examples and Comparative Examples, "parts" and "%" are shown on a weight basis. Examples 1 to 3 and Comparative Examples 1 to 3 After the fluorescent dye, the transparent solid fine particles, the water-soluble resin, the additives and the solvent were uniformly mixed in the mixing ratio (unit: parts) shown in Table 1, the pore size was 5.0 μm. The mixture was filtered through a membrane filter and purified to prepare ink compositions corresponding to each of Examples and Comparative Examples. Each ink composition was dot-printed on an unprinted postcard and a postcard whose surface was filled with black ink using an ink-jet printer, and the print was used for a fluorescence spectrophotometer to measure the fluorescence emission intensity. The results are shown in the lower part of Table 1.

In Example 1 and Comparative Example 1,
The fluorescence emission intensity when irradiated with excitation light of 365 nm was shown as a relative value when the fluorescence emission intensity in the non-printed postcard of Comparative Example 1 was set to 100. In Example 2 and Comparative Example 2, the fluorescence emission intensity when irradiated with 655 nm excitation light was shown as a relative value when the fluorescence emission intensity in the non-printed postcard of Comparative Example 2 was 100. In Example 3 and Comparative Example 3, the fluorescence emission intensity when 825 nm excitation light was irradiated was shown as a relative value when the fluorescence emission intensity in the non-printing postcard of Comparative Example 3 was 100 .

[0020]

[Table 1]

As is clear from the data shown in Table 1,
In Examples 1 to 3 , which are the ink compositions of the present invention, the fluorescence emission intensity was high, and the fluorescence emission intensity ratio between the blackened postcard and the non-printed postcard was 10% or more. On the other hand, in each of Comparative Examples 1 to 3 containing no transparent solid fine particles, the fluorescence emission intensity was low.

[0022]

As described above, the fluorescent ink composition for jet printing of the present invention contains transparent solid fine particles. Thus, an image with high fluorescence emission intensity can be formed.

Claims (1)

(57) [Claims] 1. A jet printing fluorescent ink composition containing a fluorescent dye and using water as a solvent, comprising:
Acrylic acid, methacrylic acid or N-meth
Water dispersibility grafted with tyrol acrylic amide
From nylon resin and water-dispersible egg white-chitosan reactant
A fluorescent ink composition for jet printing, comprising transparent solid fine particles having a particle size of 1 μm or less selected from the group consisting of :