JPH0114949B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to aqueous jet ink compositions. More specifically, the present invention relates to an improved water-based jet recording ink that can be used for a long time without clogging the nozzle of a jet printer, and can provide recorded matter with good light resistance. By the way, the basic printing principles of known inkjet recording methods include electrostatic attraction type, intermittent ejection type using pulse pressure, and continuous ejection using continuous pressure of several atmospheres, from the viewpoint of the method of ejecting ink droplets from the nozzle. There are methods such as types. In addition, from the viewpoint of how to control ink droplets, there are charge deflection type, electric field deflection type, and non-charge type (on-demand type). In practice, it seems that various combinations of the above-mentioned ejection methods and ink droplet control methods have been proposed and implemented, each with its own unique characteristics. However, the appropriate physical properties (viscosity, surface tension, etc.) and electrical properties of the ink differ depending on the method and the shape of the nozzle used. Therefore, in any inkjet method, ink must be continuously and stably ejected as uniform ink particles from fine nozzles. Therefore, the basic problem to be solved in inkjet printers is to completely prevent clogging of the nozzle portion and ensure continuous and stable generation of ink particles over a long period of time. Another important point is that stable ink particles can be created again after a temporary pause. Naturally, fine nozzles can become clogged even by the adhesion of even a small amount of solvent-insoluble solids. Further, even if solid matter adheres to a part of the nozzle, the direction of ink jetting changes. Therefore, in order to eject ink particles continuously and stably, not only must the viscosity and surface tension of the ink composition be appropriate, but also the solvent-insoluble solids in the ink composition must be completely removed. It is necessary to remove it. It is also necessary to completely prevent the generation of solvent-insoluble solids over time. By the way, when coloring a water-based jet ink composition, it is possible to remove or prevent the generation of solvent-insoluble solids by using a water-soluble dye. However, in systems using water-soluble dyes, it is easier to meet the basic requirements of the inkjet method, such as preventing the generation of solvent-insoluble solids, but on the other hand, the light resistance of the recorded material is insufficient. There is a drawback that arises. To be more specific, recorded characters may disappear or become difficult to read after a certain period of time, and especially in the case of color images, there may be discoloration of the image due to differences in the light fastness of the mixed dyes. occurred often. In other words, the water-soluble dyes used in conventional water-based jet ink compositions have insufficient light fastness, cause nozzle clogging, and meet various conditions necessary for jet inks such as continuous jetting properties, as well as problems with printing materials. In view of the types of colors, hues, etc. required at the time, there were naturally limitations on the types that could be used. Therefore, one of the inventors of the present invention previously proposed an ink composition containing a water-soluble ultraviolet absorber in order to improve the various drawbacks and limiting conditions mentioned above. (Japanese Patent Publication No. 56-18151) However, the requirements for light resistance in this type of market are becoming increasingly strict. In addition, it is generally known that the light resistance of a dyed product (an inkjet recorded product in the present invention) is closely influenced (interacted) by various conditions such as the substrate, coexisting substances, and environmental conditions. It is difficult to assemble a unified theoretical system regarding these problems related to photobleaching, as sufficient research results have not yet been obtained. For example, regarding substrates, well-known unique problems in interaction with substrates include the high light fastness of cationic dyed acrylic fibers and the low light fastness of nylon dyed yellow vat dyes. etc. are known. However, there is no knowledge of this kind regarding inkjet recorded matter. In order to improve the light resistance of ink jet recordings, the present inventors investigated various compounds that improve light resistance by coexisting with dyes, and found that water-soluble copper compounds (excluding copper sulfate), Alternatively, the inventors have discovered that a combination of the compound and a water-soluble quenching substance can greatly improve light resistance. At the same time, the present inventors have developed an ink composition of the present invention, that is, an aqueous jet ink, which does not generate solvent-insoluble solids that cause nozzle clogging in an inkjet system, and which does not impair the recording characteristics of inkjet recording. A novel ink composition comprising a combination of a composition, a water-soluble copper compound, or the compound and a water-soluble quenching substance has been achieved. Therefore, it is an object of the present invention to further improve the light resistance of recorded materials, to avoid clogging of nozzles, which conventionally has been unavoidable in inkjet systems, and to provide a water-soluble ink composition for use in aqueous jet ink compositions. It is an object of the present invention to provide a new aqueous jet ink composition for the purpose of expanding the types of dyes. That is, the present invention is characterized in that: (1) an aqueous jet ink composition containing a water-soluble dye, a wetting agent, and water as main components, further comprising at least one water-soluble copper compound (excluding copper sulfate); and (2) an aqueous jet ink composition containing a water-soluble dye, a wetting agent, and water as main components, further comprising at least one water-soluble copper compound (excluding copper sulfate) and a water-soluble The present invention relates to a jet ink composition containing at least one kind of quenching substance. The copper compounds used in the present invention are preferably cupric chloride, cupric bromide, copper nitrate, copper acetate,
Pyridylazonaphthol copper complex salt, ethylenediaminetetraacetic acid copper complex salt, polyethyleneimine polymer copper complex salt, aminoacrylic resin copper complex salt, reaction product of DL-α-alanine and copper, reaction product of glycine and copper, glyceric acid and copper complex salt, It is at least one selected from a reaction product, a reaction product of lactic acid and copper, and a reaction product of β-hydroxypropionic acid and copper. Particularly preferred is at least one selected from cupric chloride, cupric bromide, copper acetate, and pyridylazonaphthol copper complex salts. The water-soluble copper compound is preferably contained in an ink composition containing a water-soluble dye, a wetting agent, and water as main components in an amount of 0.1 to 5% by weight. The water-soluble copper compound is 0.1% by weight in the ink composition.
It is necessary for the above amount to be present from the viewpoint of improving light resistance, but in order to obtain a sufficient effect, it is preferable to have it present in an amount of 0.3% by weight or more. On the other hand, in view of the required properties for water-based jet ink compositions such as prevention of nozzle clogging, the water-soluble copper compound is contained in an amount of 5% by weight.
Hereinafter, it is more preferable to make it exist in an amount of 2% by weight or less. Further, as the water-soluble dye used in the aqueous jet ink composition of the present invention, any dye having good solubility in water can be used. However, the effect of the present invention is characterized in that a stronger addition effect appears in dyes with weak light resistance. Examples of the water-soluble dye include CIDirect Blue 236, CIDirect Blue 203,
CIDirect Blue 202, CIDirect Blue 15, CI
Acid Blue 7, CIAcid Blue 9, CIDirect
Blue 199, CIAcid Yellow 1, CIDirect
Red 227, CIDirect Red 225, CIAcid Red
87, CIAcid Red 92, CIAcid Red 52, CI
Acid Red 94, CIAcid Red 289, CIDirect
Examples include Black 51. Further, in the present invention, a wetting agent that is liquid at room temperature is used. Specific examples of the humectant include polyhydric alcohols such as diethylene glycol, triethylene glycol, polyethylene glycol #300, glycerin, propylene glycol, etc.
Alkyl ethers of polyhydric alcohols and their acetate esters, such as ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, tripropylene glycol methyl ether, etc.; hydroxyalkyl formamides, such as those in which the alkyl group has 1 carbon atom hydroxyalkylformamides ranging from to 4;
Alternatively, N-vinyl-2-pyrrolidone oligomer synthesized by the method described in JP-A-50-102407, etc. may be used. These humectants can be used alone or in combination. On the other hand, another embodiment of the present invention includes an aqueous jet ink composition further containing a water-soluble quencher. In this embodiment, the quenching substance, that is, the substance that deactivates the fluorescence of the excited substance through interaction [Kyoritsu Shuppan Co., Ltd., Chemistry Dictionary No. 4, p. 769], is preferably iodide. At least one compound selected from potassium, potassium bromide, potassium chloride, potassium thiocyanate, cobalt sulfate, copper sulfate, ferrous sulfate, nickel sulfate, and nickel oxalate is used. Among these, it is particularly preferable to use at least one of potassium iodide, potassium bromide, copper sulfate, cobalt sulfate, and potassium thiocyanate. The quenching substance includes a water-soluble dye, a wetting agent, a water-soluble copper compound,
and water, preferably
It is contained in a range of 0.1 to 5% by weight. Naturally, if the amount of water-soluble quenching substance used is too small, the effect of improving light resistance cannot be obtained. On the other hand, if the amount is too high, the color rendering properties tend to deteriorate and the nozzle is clogged with precipitates, so it is similarly undesirable. The aqueous jet ink composition of the present invention has, for example, the following formulation. Water soluble dye 0.1~15
% by weight, 5-40% by weight of the wetting agent, 0.1-5% by weight of the water-soluble copper compound, 0.1-5% by weight of the water-soluble quenching substance if necessary, and the remainder water. The aqueous jet ink composition of the present invention as described above preferably has a viscosity of 1.2 to 30 centipoise and a nonvolatile content of about 50% by weight or less from the viewpoint of practical use in an inkjet system. Furthermore, the PH etc. of the ink can vary widely,
Depending on the type and pH of the quenching substance, precipitation may occur, so it is preferable to adjust the amount appropriately before use. For example, copper sulfate, cupric chloride, copper acetate, copper nitrate, cupric bromide, etc. are preferably used at a pH of 4.0 or lower, or adjusted with ammonia or an organic amine to a pH of 10.5 or higher. The aqueous jet ink composition of the present invention may further contain a water-soluble solvent, such as dioxane, acetone, diacetone alcohol, alkyl alcohol having 1 to 3 carbon atoms, dimethylformamide, dimethyl sulfoxide, N -Methyl-
You may use 2-pyrrolidone etc. 1 type, or 2 or more types. If necessary, as a surface tension adjuster,
Cationic surfactants, such as sodium alkyl acetate; anionic surfactants, such as alkylpyridium sulfates; nonionic surfactants, such as polyoxyethylene alkyl ether; or amphoteric surfactants. You may. Furthermore, if necessary, viscosity modifiers such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol; sodium dehydroacetate, 1,2-
Amine salt of benzisothiazolin-3-one, 6
A small amount of a fungicide or preservative such as -acetoxy-2,4-dimethyl-m-dioxane may also be added. Further, oxygen absorbers such as sodium sulfite and sodium hydrogen sulfite can also be used in combination. The aqueous jet ink composition of the present invention thus obtained completely satisfies the requirements and performance of the inkjet system, such as prevention of nozzle clogging. Moreover, the light resistance of the recorded material can be significantly improved. In addition, it is possible to expand the so-called range of selection by using various water-soluble dyes. As a result of the above, its industrial effects are immeasurable. Hereinafter, the present invention will be specifically explained with reference to Examples. However, there is no intention to limit it to these specific examples. Examples 1 to 24 Ink raw materials were stirred and mixed for 0.5 hours or more at various ratios shown in Tables 1 and 2,
Each raw material was dissolved in water. The mixture was then pressure-filtered through a 1.2μ membrane filter manufactured by Millipore Co., Ltd. to obtain an aqueous jet ink composition. These aqueous jet ink compositions were then continuously recorded using an on-demand inkjet printer, and the continuous jetting stability was evaluated based on the recording state after 100 hours and the print quality of the recorded matter. Regarding light resistance, after irradiating the recorded material for a predetermined time using a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) (irradiation energy 464 joules/cm ² hr), a reflection densitometer (RD915, manufactured by Macbeth) was used. The degree of fading was compared using the ratio of optical density to the initial value (100). The results obtained are shown in Tables 1 and 2. Comparative Examples 1 to 2 Water-based jet ink compositions were prepared from the compositions shown in Table 2, which were conventionally thought to have good light resistance, in the same manner as in the above Examples. The resulting composition was tested for continuous jet stability and light resistance in the same manner as in the Examples.

【table】

【table】

[Table] As is clear from the results in Tables 1 and 2 above, the jet ink composition of the present invention has good continuous jetting stability without impairing the jetting characteristics in the inkjet system, and moreover, It also has extremely good light resistance.

Claims (1)

[Claims] 1. An aqueous jet ink composition containing a water-soluble dye, a lubricant, and water as main components, further comprising at least one water-soluble copper compound (excluding copper sulfate).
A jet ink composition comprising seeds. 2 The copper compound is present in the jet ink composition in an amount of 0.1
The jet ink composition according to claim 1, wherein the jet ink composition contains 5% by weight. 3 The copper compound includes cupric chloride, cupric bromide,
Copper nitrate, copper acetate, reaction product of lactic acid and copper, reaction product of glyceric acid and copper, pyridylazonaphthol copper complex, ethylenediaminetetraacetic acid copper complex, reaction product of glycine and copper, DL-α-alanine and copper The jet ink composition according to claim 1, which is at least one selected from the group consisting of a reaction product of β-hydroxypropionic acid and copper, a polyethyleneimine polymer copper complex salt, and an aminoacrylic resin copper compound. 4. An aqueous jet ink composition containing a water-soluble dye, a wetting agent, and water as main components, which further contains at least one water-soluble copper compound (excluding copper sulfate) and at least one water-soluble quenching substance. A jet ink composition characterized by: 5 The copper compound is present in the jet ink composition in an amount of 0.1
The jet ink composition according to claim 4, wherein the jet ink composition contains 5% by weight. 6. The jet ink composition according to claim 4, wherein the water-soluble quenching substance is contained in the jet ink composition in an amount of 0.1 to 5% by weight. 7 The copper compound includes cupric chloride, cupric bromide,
Copper nitrate, copper acetate, reaction product of lactic acid and copper, reaction product of glyceric acid and copper, pyridylazonaphthol copper complex, ethylenediaminetetraacetic acid copper complex, reaction product of glycine and copper, DL-α-alanine and copper 5. The jet ink composition according to claim 4, which is at least one selected from the group consisting of a reaction product of β-hydroxypropionic acid and copper, a polyethyleneimine polymer copper complex salt, and an aminoacrylic resin copper compound. 8. A patent in which the water-soluble quenching substance is at least one selected from potassium iodide, potassium bromide, potassium chloride, potassium thiocyanate, cobalt sulfate, copper sulfate, ferrous sulfate, nickel sulfate, and nickel oxalate. The jet ink composition according to claim 4.