JP3149722B2 - Recording liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording liquid which becomes visible when irradiated with ultraviolet rays. More specifically, the present invention relates to an ink jet recording liquid that emits red light when irradiated with ultraviolet light and has excellent water resistance.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording liquid has been prepared by dissolving a water-soluble dye such as an acid dye, a direct dye, or a basic dye in a glycol solvent and water (Japanese Patent Application Laid-Open No.
1412, JP-A-54-89811, JP-A-55-6511
269) is often used. As the water-soluble dye, a dye having high solubility in water is generally used in order to obtain the stability of the recording liquid. Therefore, the ink jet recorded matter generally has poor water resistance, and there is a problem that spilling water easily causes dye bleeding of a recorded portion.

In order to improve such poor water resistance,
Attempts have been made to change the structure of the dye or to prepare a recording solution having a strong basicity (JP-A-56-57862). It has also been attempted to improve the water resistance by making good use of the reaction between the recording paper and the recording liquid (Japanese Patent Laid-Open No. 50900/1979).
4, JP-A-57-36969, JP-A-59-2069
6, JP-A-59-146889). These methods have a remarkable effect on certain types of recording paper. However, since various types of recording paper are used in recording by the ink jet method, when a recording medium other than a specific type of recording paper is used, a sufficient amount of recorded material can be obtained. Water resistance often cannot be obtained, and lacks versatility.

[0004] Examples of a recording liquid having good water resistance include a liquid in which an oil-soluble dye is dispersed or dissolved in a high boiling point solvent and a liquid in which an oil-soluble dye is dissolved in a volatile solvent. As a result, there are various restrictions on a material that can emit light and visualize a recorded matter, and it is difficult to adjust such a recording liquid. In addition, conventionally, for various special applications, it is difficult to confirm with ordinary light, but inks that can be visualized by special light or read by a sensor have been developed. Heretofore, for such an application, a substance that emits purple light such as a fluorescent whitening agent has been used. Since such a fluorescent whitening agent is an aqueous dye, there is a disadvantage that the recorded matter has poor water resistance. Further, since the fluorescent whitening agent is widely used for paper, fiber and the like, there is also a disadvantage that it is difficult to distinguish the light emission from the light emission. Fluorescent pigments, which are particles of a fluorescent dye made of resin, are a mixture of a fluorescent dye and a resin. When an organic solvent is used, it can be dissolved and used like a dye, but it has absorption in the visible region. In other words, the displayed characters and figures can be visually checked even when no fluorescent light is applied, and cannot be used as a material for so-called hidden ink.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording liquid capable of obtaining a water-resistant recording material which emits red light when irradiated with ultraviolet rays.

[0006]

That is, the present invention relates to an ink jet recording liquid containing a fluorescent material represented by the following general formula.

Embedded image The fluorescent material is irradiated with ultraviolet light of 254 nm to 365 nm.
It emits light at about 00 to 650 nm, especially around 620 nm. Further, when ultraviolet rays are not irradiated, since it is not colored, identification is not easy, and it is useful as a so-called hidden ink material. The fluorescent material is 4,4,4─
Trifluoro-1- (2-furanyl) -1,3-butanedione compound or 4,4,4-trifluoro-1
Tetra- (2-methyl) -1,3-butanedione compound produced by reacting europium perchlorate with sodium hydroxide in acetone.
Tetra 4,4,4-trifluoro-1- (2-furanyl) having n-butylammonium salt or water as a counter ion
-1,3-butanedionate] europium complex or tetra-4,4,4-trifluoro-1- having tetra-n-butylammonium salt or water as a counter ion
(2-methyl) -1,3-butanedionate] europium complex, which is represented by the following formulas (a) to (d).

[0007]

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[0008]

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[0009]

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[0010]

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Each of these compounds has the property of being colorless under visible light and red under ultraviolet light, has a high luminous intensity, and is excellent in light resistance and the like.
These compounds may be used alone or in combination of two or more. These compounds have little solubility in water, but have sufficient solubility in solvents, so that the recorded matter has good water resistance and is extremely suitable as a fluorescent material for inkjet printing for hidden printing.

In the present invention, since the emission intensity of the fluorescent material is high, the desired detection as a hidden print can be made by using 0.05 to 3% by weight in the recording liquid. If the amount is smaller than this range, it becomes difficult to read the light emission. If the amount is larger than this range, precipitation is liable to occur and troubles such as clogging of a nozzle are liable to occur.

In the present invention, the fluorescent material is dissolved in a solvent and used as a recording liquid. As the solvent used, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, alcohol solvents such as methanol, ethanol and propanol, ester solvents such as ethyl acetate, dimethyl sulfoxide, N Cellosolve solvents such as -methyl-2-pyrrolidone, γ-butyl lactone, dioxane, methyl cellosolve, ethyl cellosolve, and butyl cellosolve.

The recording liquid of the present invention can be selected from various types of printers and various printers by selecting the type of solvent, the presence / absence, type and amount of binder, and the like, and adjusting the viscosity, surface tension, conductivity, drying property and the like. Can be applied to the recording medium. The characteristics required for the recording liquid differ depending on the printer, but generally the viscosity is 0.8 to 15 cps and the surface tension is 20 to
55 dyn / cm is required. When used in a continuous type printer, it is desirable to adjust the conductivity to about 0.1 to 20 mS. When an absorptive recording medium such as paper is used, it is preferable to use the recording liquid as described below. That is, the fluorescent material of the present invention,
It is prepared by adding a solvent and, if necessary, a binder component and an additive.

The binder component (resin) is for fixing the fluorescent material satisfactorily. The binder component (resin) has good solubility in the above-mentioned solvent and can appropriately adjust the viscosity of the recording liquid. Can be mentioned. That is, vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride, cellulose, petroleum resin, phenol resin, epoxy, epoxy phenol, natural resin (arabic gum, gelatin, etc.), acrylic, styrene-acryl Dissolved in the above solvents such as polyester, polyester, polyamide, polyurethane, butyral, silicone, rosin, rosin modified resin (phenol, maleic acid, fumaric acid resin, etc.), rubber, acrylamide, alkyd, shellac, etc. Resin is used. These resins are required when recording on a non-permeable recording medium, and are used in the recording liquid in an amount of 0.5 to 10% by weight, preferably 1 to 5% by weight. If the amount is less than this amount, the fluorescent material cannot be sufficiently fixed to the impermeable recording medium. If the amount is larger than this amount, the ejection stability of the recording liquid may be reduced. In addition, a resin layer thickly covers the periphery of the fluorescent material, which may not only cause a decrease in light emission of the fluorescent material but also cause a problem of generation of fluorescence caused by the resin.

In the present invention, in addition to the solvent for dissolving the fluorescent material that emits fluorescent light by ultraviolet irradiation,
Prevents drying of the recording liquid at the nozzle and solidification of the recording liquid,
As a solvent for preventing stable jetting of the recording liquid and drying of the nozzle over time, the following solvents can be added and used. Such solvents include ethylene glycol, diethylene glycol, propylene glycol,
Triethylene glycol, polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether ethylene glycol monoethyl ether, 1,2─
Examples include hexanediol, substituted pyrrolidone, 2,4,6-hexanetriol, tetrafurfuryl alcohol, 4-methoxy-4-methylpentanone, and the like. These solvents are used alone or as a mixture in the range of 0 to 50% of the recording liquid.

When the printing medium is paper, a penetrant can be added to stop the permeation of the recording liquid into the paper and to increase the apparent dryness. Such penetrants include:
Glycol ethers such as diethylene glycol monobutyl ether, alkylene glycol, polyethylene glycol monolauryl ether, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium oleate, sodium dioctylsulfosuccinate and the like can be used. These have sufficient effects when the used amount of the recording liquid is 5% or less. If the amount is more than 5%, bleeding of printing and paper dropout (print-through) occur, which is not preferable.

Further, an antifoaming agent can be added in order to prevent the circulation or movement of the recording liquid and the generation of bubbles during the production of the recording liquid. Anionic, non-ionic, cationic,
Surfactants such as amphoteric surfactants can be used.

Although the recorded matter of the present invention is difficult to discern visually, it is also possible to use a coloring agent to make it easy to identify the recorded matter. For this reason, a general pigment or dye can be used together with the fluorescent material in the recording liquid. However, 3% of the recording liquid
Below, preferably less than 2%.
As the dye, an oily dye, a metal-containing dye, a disperse dye, or the like is used. These dyes are preferably purified dyes from which inorganic salts have been removed.

For the production of the recording liquid, a fluorescent material, a solvent, a resin, an additive, etc. are mixed as needed, dissolved by stirring, diluted if necessary, and mixed with other additives to prepare the recording liquid. To manufacture. Mixing and stirring can be performed by a high-speed disperser, emulsifier, or the like, in addition to stirring by a stirrer using a normal blade. Before or after dilution, the mixed recording liquid is sufficiently filtered with a filter having a pore size of 3 μm or less. Preferably, the filtration is carried out with a filter of 1.0 μ or less. Coarse particles can be removed by centrifugation prior to filtration of the filter, thereby reducing filter clogging and filter replacement.

The recording liquid manufactured according to the present invention has remarkably good water resistance and is therefore preferably used as an ink jet recording liquid, and can be used for hidden letters, symbols, cardboard markings, numbering, bar codes, etc. in office documents. It can be used in the field of hard-to-recognize recordings and recordings with security functions. Further, it has better water resistance than a recording solution produced by using a dye such as a fluorescent whitening agent, and can form a special image having excellent preservability of a recorded matter.

[0022]

The present invention will be described below in further detail with reference to examples. In the examples, parts and% represent parts by weight and% by weight, respectively.

[Synthesis of Fluorescent Material] Synthesis of Compound (a) 3.6 parts of europium oxide and 10 parts of water were mixed with perchloric acid (6 parts).
(0% aqueous solution) was added and stirred at room temperature for 30 minutes. This aqueous solution was added to 4,4,4-trifluoro {1} (2
{Furanyl) {1,3} butanedione 16.5 parts. The mixture was added dropwise at room temperature to a mixture of 3.2 parts of sodium hydroxide, 5 parts of water and 250 parts of acetone, and stirred for 1 hour. After the reaction is over,
The acetone was removed with an evaporator, and the resulting yellow paste-like solid was dissolved in 50 parts of ethanol.
It dropped into 00 parts. The precipitated white solid was separated by filtration and dried,
15.5 parts of a compound (a) represented by the following formula was obtained.

[0024]

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Synthesis of Compound (b) 10 parts of the compound (a) was dissolved in 200 parts of ethanol, and 6 parts of tetra-n-butylammonium bromide was added.
After stirring at room temperature for 1 hour, 500 parts of water was added, and the precipitated solid was separated by filtration and dried under reduced pressure at 50 ° C. to obtain 11.5 parts of a compound (b) represented by the following formula.

[0026]

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Synthesis of Compound (c) Perchloric acid (6) was added to 3.6 parts of europium oxide and 10 parts of water.
(0% aqueous solution) was added and stirred at room temperature for 30 minutes. This aqueous solution was added to 4,4,4-trifluoro {1} (2
{Methyl) {1,3} butanedione 16.5 parts. The mixture was added dropwise at room temperature to a mixture of 3.2 parts of sodium hydroxide, 5 parts of water and 250 parts of acetone, and stirred for 1 hour. After the reaction is over,
The acetone was removed with an evaporator, and the resulting yellow paste-like solid was dissolved in 50 parts of ethanol.
It dropped into 00 parts. The precipitated white solid was separated by filtration and dried,
15.5 parts of a compound (c) represented by the following formula was obtained.

[0028]

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Synthesis of Compound (d) 10 parts of this compound (c) was dissolved in 200 parts of ethanol, and 6 parts of tetra-n-butylammonium bromide was added.
After stirring at room temperature for 1 hour, 500 parts of water was added and the precipitated solid was separated by filtration and dried under reduced pressure at 50 ° C. to obtain 11.5 parts of a compound (d) represented by the following formula.

[0030]

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Example 1 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (a)) 0.3 part Petroleum solvent (Shellsol AB manufactured by Shell Chemical) 30.7 parts Dimethyl sulfoxide 15.0 parts N-methyl-2-pyrrolidone 54.0 parts 20 with a stirrer After dissolving the solution, the solution was filtered through a 0.45 μm membrane filter to produce a recording solution. The filterability during the production of the recording liquid, the viscosity of the recording liquid, the surface tension, the light emission when the recorded matter was irradiated with ultraviolet rays, the water resistance of the recorded matter, the adhesion and the like were evaluated. Each evaluation method is shown below, and the results are shown in Table 1. Note that recording was performed on plain paper using a piezo-type printer. [Filterability]: 0.45 μm membrane filter (4.5
(cmφ) when the filtration amount under reduced pressure was 1 liter or more. [Viscosity]: VM-IA-L (manufactured by Yamaichi Denki) [Surface tension]: Wilhelmy method surface tensiometer (manufactured by Kyowa Kagaku) [Water resistance]: Water was dripped on the recording surface to check the bleeding of the ink. [Adhesion]: Peeling test using a mending tape (3M). [Emission]: The recorded matter was irradiated with ultraviolet rays, and the emission state was visually confirmed.

Example 2 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (b)) 0.3 part Methyl ethyl ketone 80.0 parts Ethyl acetate 5.0 parts N-methyl-2-pyrrolidone 15.0 parts Sodium thiocyanate 1.0 part After dissolving with a stirrer for 20 minutes, 0 The solution was filtered through a 0.45 μm membrane filter to produce a recording solution. Instead of a piezo-type printer, Hitachi IJ
Various evaluations were made in the same manner as in Example 1 except that a “printer” (continuous type) was used, and the electric motor of the recording liquid was also measured. Table 1 shows the results.

Example 3 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (c)) 1.0 part Vinyl chloride-vinyl acetate copolymer (VYMH manufactured by Union Carbide) 1.0 part Methyl ethyl ketone 80.0 parts Ethyl acetate 11.0 parts N-methyl-2-pyrrolidone 2 0.0 parts Ethyl alcohol 5.0 parts Sodium thiocyanate 1.0 part After dissolving with a stirrer for 30 minutes, the mixture was filtered through a 0.45 μm membrane filter to produce a recording liquid. Various evaluations were made in the same manner as in Example 2. Table 1 shows the results.

Example 4 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (a)) 0.5 part Vinyl chloride-vinyl acetate copolymer (VYMH manufactured by Union Carbide) 1.0 part Methyl ethyl ketone 80.0 parts Ethyl acetate 11.0 parts N-methyl-2-pyrrolidone 1 2.0 parts γ-butyl lactone 2.0 parts Ethyl alcohol 5.0 parts Sodium thiocyanate 1.0 parts After dissolving with a stirrer for 30 minutes, the solution was filtered through a 0.45μ membrane filter to produce a recording solution. Various evaluations were made in the same manner as in Example 2. Table 1 shows the results.

Example 5 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (b)) 0.7 parts AT-100 (Acrylic resin solution NV50%, manufactured by Toyo Ink Mfg. Co., Ltd.) 5 parts Cyclohexanone 5 parts Aluminum chelating agent (Algomer S, manufactured by Kawaken Fine Chemicals) 0.5 part Methyl ethyl ketone 78 parts Toluene 6 parts Sodium thiocyanate 1.3 parts Ethyl acetate 11.0 parts N-methyl-2-pyrrolidone 1.0 part Add 10 parts of methyl ethyl ketone to the fluorescent material, resin solution, and chelating agent and dissolve well. Then, the mixture was diluted with the remaining solvent, and sodium thiocyanate was added to adjust the recording liquid. Thereafter, the solution was filtered through a 0.8 μm membrane filter and then filtered through a 0.45 μm membrane filter to produce a recording solution. Various evaluations were made in the same manner as in Example 2. Table 1 shows the results.

Example 6 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (d)) 0.5 part Diethylene glycol monobutyl ether 5.0 parts Dimethyl sulfoxide 15.0 parts N-methyl-2-pyrrolidone 77.0 parts After dissolving with a stirrer for 20 minutes, 0.45 μm The solution was filtered through a membrane filter to produce a recording solution. Various evaluations were made in the same manner as in Example 1. Table 1 shows the results.

Example 7 A recording liquid was prepared by mixing the following raw materials. Fluorescent material (compound (c)) 0.4 part Diethylene glycol monobutyl ether 5.0 parts Dye (Varifast Red 1306 manufactured by Orient Chemical) 2.0 parts Dimethyl sulfoxide 5.0 parts Ethylene glycol 2.0 parts Isopropyl alcohol 10 0.0 part N-methyl-2-pyrrolidone 77.0 parts After dissolving with a stirrer for 20 minutes, the mixture was filtered through a 0.45 μm membrane filter to prepare a recording solution. Instead of a piezo printer, Marsh L Marsh
Various evaluations were made in the same manner as in Example 1 except that recording was performed on cardboard using “CP”. Table 1 shows the results.

Example 8 A recording liquid was prepared and evaluated in the same manner as in Example 7 by mixing the following raw materials. Table 1 shows the results. 1. Fluorescent material (compound (d)) 1.0 part Ethyl cellosolve 77.0 parts N-methyl-2-pyrrolidone 10.0 parts Triethylene glycol monobutyl ether 10.0 parts Dye (Varifast Red 1308 manufactured by Orient Chemical) 0 copies

[0039]

[Table 1]

[0040]

According to the present invention, it is possible to obtain a recording liquid having excellent solubility and excellent discharge stability. Further, a recorded matter having good water resistance can be obtained. This record can be used to make a record that is difficult to discriminate from the base of paper or the like, and emits red light due to ultraviolet light, so it is read as a special record by a sensor, hidden characters, printing related to security, etc. Available to

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-140105 (JP, A) JP-A-63-150358 (JP, A) JP-A-57-186170 (JP, A) JP-A-4- 220395 (JP, A) U.S. Pat. No. 3,359,941 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (2)

(57) [Claims] 1. An ink jet printer comprising a fluorescent material represented by the following general formula dissolved in a solvent.
Non-aqueous recording liquid. Embedded image Wherein X is CH ₃ , or Y _{is, (n-C 4 H 9} ) 4 N +, or (H ₂ O) _n (n is 0
To 2). 2. The ink jet recording liquid according to claim 1, comprising 0.05 to 3.0% by weight of a fluorescent material.