JP2003026964A - Fluorescent color ink for ink jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent color ink for ink jet which has a bright fluorescent color and a good color reproducibility and is excellent in light resistance and emission stability. SOLUTION: This fluorescent color ink contains a dispersoid comprising cores containing a fluorescent colorant and a polymer and having shells formed thereon from a polymer having hydrophilic groups, a water-soluble organic solvent, and water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet fluorescent color ink, and more particularly to an inkjet fluorescent color ink having a bright fluorescent color and excellent color reproducibility, light resistance and emission stability.

[0002]

2. Description of the Related Art In recent years, the progress of ink jet recording technology has been remarkable, and it has become possible to obtain a high-definition image which is very close to a photograph.

As a result, ink jet recording is applied to printed matter such as posters, and in order to improve its appeal, the use of fluorescent colors is a powerful means.

However, inks using fluorescent dyes have hitherto been used.
The light resistance was poor and the stability in the ink was poor. In particular, when the fluorescent dye is present in a dispersed state, the stability of the dispersion is poor, the stability of the emission is poor, and it is difficult to express the original vividness of the fluorescent color.

However, when the fluorescent color is mixed with the basic color of yellow, magenta, or cyan to form a mixed color, there is a possibility that a special shade can be expressed. It has been pointed out that the light resistance and the emission stability are important, and the reproducibility, vividness, light resistance and emission stability of these superposed colors have been demanded.

[0006]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a fluorescent color ink for ink jet and an ink set which have a bright fluorescent color, good color reproduction, and excellent light resistance and emission stability.

[0007]

The above object of the present invention can be achieved by the following constitutions.

1) An inkjet fluorescent color ink having a dispersoid having a core containing a fluorescent coloring material and a polymer, and a shell made of a polymer having a hydrophilic group formed on the outside thereof, a water-soluble organic solvent and water, 2) Ink jet fluorescent color ink according to 1, wherein the fluorescent color material is an oil-soluble dye, 3) Ink jet fluorescent color ink according to 1, wherein the fluorescent color material is a pigment, 4) Fluorescence as a fluorescent color material An inkjet fluorescent color ink containing a dispersoid in which a pigment and a polymer are mixed, and a dispersion medium composed of water and a water-soluble organic solvent, 5) Any of 1 to 4 in which the average particle diameter of the dispersoid is 50 to 200 nm. 6. The inkjet fluorescent color ink according to item 1, 6) The inkjet fluorescent color ink according to 5, wherein the average particle size of the dispersoid is 50 to 120 nm, 7) Yellow In , Magenta ink, cyan ink,
An inkjet fluorescent color ink set comprising a black ink and the fluorescent color ink according to any one of 1 to 4, 8) a yellow ink, a magenta ink, a cyan ink,
The inkjet fluorescent color ink set according to 7, wherein the black ink is a pigment ink, and the present invention is described in detail below.

The present invention according to claim 1 has a dispersoid in which a fluorescent coloring material forms a core together with a polymer, and a shell made of a polymer having a hydrophilic group is formed on the outside thereof, a water-soluble organic solvent and water. The fluorescent coloring material includes both a water-soluble coloring material and a water-insoluble coloring material.

From the viewpoint of image storability, a water-insoluble coloring material is preferable, and a method in which the water-insoluble coloring material is mixed with a polymer and added as dispersed particles to the ink is more preferable.

The water-insoluble fluorescent coloring materials include dyes and pigments. The dyes preferably used in the present invention are listed below, but the present invention is not limited thereto.

C. I. Solvent Yellow 44 C. I. Solvent yellow 82 C. I. Solvent Yellow 116 C. I. Solvent Red 43 C. I. Solvent Red 44 C. I. Solvent Red 45 C. I. Solvent Red 49 C. I. Solvent Red 60 Solvent blue 5 Solvent pink Solvent Green 7 Disperse Yellow 121 Disperse Yellow 124 Disperse Yellow 82 Disperse Orange 11 Disperse Red 58 Disperse Red 60 Disperse Blue 7 Rhodamine Eosin Etc.

Next, the pigments preferably used in the present invention are listed below, but the present invention is not limited thereto.

Lumogen Brilliant Yellow Lumogen L Yellow Lumogen L Red Lumogen L Orange Lumogen Brilliant Green7 Fine particles formed from a mixture of the above-mentioned fluorescent dye and a polymer, examples of which can be used as a core, include:

[0015] Sterling 810 YELLOW 27 Sterling 911 YELLOW 27 Sterling 850 YELLOW 27 Sterling 911 YELLOW 27 Sterling 210 YELLOW 27 Sterling 810 CERISE 13 Sterling 810 PINK1 Sterling 810 RED Sterling 911 MAZENTA 10 Sterling 911 PINK1 Sterling 911 RED Sterling 850 STRONG MAGEN
TA 21 Sterling 850 MAGENTA 10 Sterling 850 PINK 1 Sterling 210 MAGENTA 21 Sterling 210 PINK 1 Examples of fluorescent dyes and fluorescent pigments include diglo (D
ayglo ™ Fire orange, Digro ™ Saturn yellow, Digro ™ Rocket red, Digro ™ Horizon blue, pyranine, fluorescein, rhodamine B and the like.

The commercially available fluorescent pigment dispersions containing these fluorescent pigments are shown below. That is, a fluorescent pigment is an aqueous dispersion obtained by dispersing in water by a surfactant,
Details of each fluorescent pigment liquid are as follows.

A: Trade name SW-15 (manufactured by Shin Loihi Co., Ltd.) Yellow fluorescent pigment 42% by mass Average particle diameter 0.8 μm Cumulative distribution 100% of particles having a particle diameter of 0.2 to 2.0 μm B; Trade name SW -17 (manufactured by Shin Loihi Co., Ltd.) Pink fluorescent pigment 42 mass% Average particle size 0.8μ
m Cumulative distribution of particles having a particle diameter of 0.2 to 2.0 μm 100% C; trade name Lumicol NKW-3005 (manufactured by Nippon Fluorescent Co., Ltd.) D; trade name Lumicol NKW-3007 (manufactured by Nippon Fluorescent Co., Ltd.) Pink Color fluorescent pigment 41% by mass Average particle size 0.11
When the μm fluorescent coloring material is a fluorescent dye, the colored particles of the core can be prepared by various methods. For example, the oil-soluble fluorescent dye is dissolved in the monomer, after emulsification in water, a method of encapsulating the fluorescent dye in the polymer by polymerization, the polymer and the fluorescent dye are dissolved in an organic solvent, after emulsification in water, Examples thereof include a method of removing the organic solvent. The colored fine particles are further coated with a polymer to form a shell.

When the fluorescent coloring material is a fluorescent pigment, a method in which the fluorescent pigment is kneaded with a polymer and then dispersed in an aqueous system to prepare a polymer-coated pigment core, a solution in which the polymer is dissolved in an organic solvent is made fluorescent. After adding to the pigment dispersion, the solvent is removed under reduced pressure to coat the polymer, and the like.

Next, a method of forming a shell will be described. As the method for providing the polymer shell, a method of adding a water-soluble polymer dispersant to the aqueous suspension of the core and adsorbing it, a method of gradually dropping a monomer and depositing it on the core surface at the same time as the polymerization, or a method of dissolving it in an organic solvent There is a method in which the polymer is gradually dropped and adsorbed on the core surface simultaneously with precipitation.

Further, a method of forming the core shell in one step can be considered. For example, a method of dissolving or dispersing a polymer serving as a core and a fluorescent coloring material in a polymer serving as a shell, polymerizing after suspension in water, or emulsion polymerization while gradually adding the liquid to water containing an active agent micelle. There is a way to go.

In this case, the amount of the polymer used in the shell is preferably 5 to 95% by mass, more preferably 10 to 90% by mass based on the total amount of the polymer. If it is less than 5% by mass, the thickness of the shell is insufficient, and a part of the core containing a large amount of fluorescent coloring material is likely to appear on the particle surface. Further, if the shell polymer is too much, the fluorescent coloring material protecting ability of the core tends to be lowered.

The amount of the fluorescent coloring material is preferably 20 to 1000% by mass based on the total amount of the polymer. If the amount of the fluorescent coloring material is too small as compared with the polymer, the image density after ejection does not increase, and if the amount of the fluorescent coloring material is too large, the polymer cannot be sufficiently protected.

Next, the evaluation of core shell formation will be described. It is important to evaluate whether or not the core particles are actually core-shelled.
The analysis method is limited from the viewpoint of resolution because it is extremely small as m or less.

A transmission electron microscope (TEM), a time-of-flight secondary ion mass spectrometer (TOF-SIMS) and the like can be applied as the analysis method for such purpose.

When observing the fine particles formed into core shells by TEM, the dispersion can be applied on the carbon support film, dried and observed. Since the TEM observation image is usually monochrome, it is necessary to stain the fine particles in order to evaluate whether or not it is core-shelled. Fine particles of only the core are dyed and the TEM observation is performed to compare with the one provided with the shell.

Further, the fine particles provided with the shell and the fine particles not provided with the shell are mixed and dyed, and it is confirmed whether or not the ratio of the fine particles having different degrees of dyeing coincides with the presence or absence of the shell.

In the TOF-SIMS method, it is confirmed that the amount of the fluorescent coloring material near the surface is reduced by providing the shell on the surface of the particles, compared with the case where only the core is used. If the fluorescent coloring material contains an element that is not contained in the core-shell polymer,
By using the element as a probe, it is possible to confirm whether or not a shell having a low content of the fluorescent coloring material is provided.

In the absence of such an element, the coloring material content in the shell can be confirmed by using an appropriate dyeing agent in comparison with that without the shell.

That is, the core-shell formation can be observed more clearly by embedding the core-shell particles in an epoxy resin, preparing an ultrathin section with a microtome, and dyeing.

When the polymer or the fluorescent coloring material has an element that can be a probe, the composition of the core shell by TEM,
It is also possible to estimate the distribution amount of the fluorescent coloring material in the core shell.

In order to obtain the required particle size, it is important to optimize the formulation and select an appropriate emulsification method.

The formulation depends on the fluorescent coloring material and polymer used, but since it is a suspension in water (aqueous dispersion), it is generally necessary for the shell polymer to be more hydrophilic than the core polymer.

The coloring material contained in the shell polymer is preferably less than that in the core polymer, and the coloring material also needs to be less hydrophilic than the shell polymer. Hydrophilicity and hydrophobicity can be estimated using, for example, the solubility parameter (SP).

Regarding the solubility parameter, its value, measurement and calculation method are described in POLYMER HANDBOOK No. 4
Edition (JOHN WILEY & SONS, INC.)
The description on page 675 is helpful.

The polymer used for the colored fine particles has an average molecular weight of 500 to 100,000, especially 10
It is preferably from 0 to 30,000 from the viewpoints of film-forming property after printing, durability and formability of suspension.

Although various kinds of polymers can be used, it is preferable to use one having a glass transition temperature (hereinafter, also referred to as Tg) of 10 or more.

In the present invention, all generally known polymers can be used, but particularly preferred polymers are those having an acetal group as the main functional group, those having a carbonic acid ester group, and those having a hydroxyl group. And a polymer having an ester group.

The above-mentioned polymer may have a substituent, and the substituent may have a linear, branched or cyclic structure. Various polymers having a functional group are commercially available, but they can be synthesized by a conventional method. Further, these copolymers can also be obtained, for example, by introducing an epoxy group into one polymer molecule and then polycondensing it with another polymer or performing graft polymerization using light or radiation.

Examples of the polymer having an acetal group as a main functional group include polyvinyl butyral and the like. For example, # 2000-L, # 3000-1, # 300
0-2, # 3000-4, # 3000-K, # 4000
-1, # 4000-2, # 5000-A, # 6000-
C, # 6000-EP (above, manufactured by Denki Kagaku Kogyo)
Or BL-1, BL-1H, BL-2, BL-2H, B
L-5, BL-10, BL-S, BL-SH, BX-1
0, BX-L, BM-1, BM-2, BM-5, BM-
S, BM-SH, BH-3, BH-6, BH-S, BX
-1, BX-3, BX-5, KS-10, KS-1, K
S-3, KS-5 (above, Sekisui Chemical Co., Ltd. product), etc. are mentioned.

Polyvinyl butyral is obtained as a derivative of polyvinyl alcohol (PVA), but the acetalization of the hydroxyl groups of the original PVA is about 80 mol% at the maximum, and usually about 50 to 80 mol%. It should be noted that the acetal mentioned here does not refer to a 1,1-diethoxyethane group in a narrow sense, but refers to an orthoaldehyde compound in general.

The hydroxyl group is not particularly limited, but it is 10
It is preferable that the content is ˜40 mol%. The acetyl group content is not particularly limited, but is preferably 10 mol% or less.

The polymer having an acetal group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer form an acetal group.

In addition, as a polymer whose main functional group is an acetal group, Iupital series manufactured by Mitsubishi Engineering Plastics Co., Ltd. can be used.

Examples of the polymer having a carbonic acid ester group as a main functional group include polycarbonates such as Iupilon series and Novarex series (manufactured by Mitsubishi Engineering Plastics Co., Ltd.).

Iupilon series is bisphenol A
It is produced by using as a raw material, and its value varies depending on the measuring method, but various molecular weights can be used.

In the Novarex series, the molecular weight is 20
000-30000, glass transition temperature (Tg) 150 ° C
However, the present invention is not limited to these.

The polymer having a carbonic acid ester group as a main functional group means that among oxygen atoms contained in the polymer,
It means that at least 30 mol% or more contributes to the formation of a carbonic acid ester group.

Examples of the polymer having a hydroxyl group as a main functional group include PVA. Although the solubility of PVA in organic solvents is low in many cases, the solubility of PVA in organic solvents increases if the saponification value is low.

It is also possible to use PVA having high water-solubility by adding it to the aqueous phase, removing the organic solvent, and adsorbing it to the polymer suspension.

Commercially available PVA can be used, for example, Poval PVA-102 and PVA-11.
7, PVA-CSA, PVA-617, PVA-505
(These are products manufactured by Kureha Chemical Co., Ltd.), PVA for special brands of sizing agents, PVA for hot melt formation and other functional polymers KL-506, C-118, R-1130, M
-205, MP-203, HL-12E, SK-510
2 or the like can be used.

The degree of saponification is generally 50 mol% or more, but it can be used even if it is about 40 mol% as in LM-10HD. Other than PVA, those having a hydroxyl group as a main functional group can be used, but those having at least 20 mol% or more of the oxygen atoms contained in the polymer forming a hydroxyl group are preferable.

Examples of the polymer having an ester group as a main functional group include methacrylic resin, and Delpet series 560F, 60N, 80N, LP-1,
SR8500, SR6500 (manufactured by Asahi Kasei Corp.) and the like can be used.

The polymer having an ester group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer form an ester group.

These polymers may be used either individually or in combination of two or more. Further, other polymers and inorganic fillers may be contained as long as these polymers are contained in a mass ratio of 50% or more.

Although it is preferable to use a copolymer of these polymers, for example, as a method of copolymerizing a polymer having a hydroxyl group with various polymers, the hydroxyl group is reacted with a monomer having an epoxy group such as glycidyl methacrylate, and then, It can be copolymerized with a methacrylic acid ester monomer by suspension polymerization.

In the fluorescent color ink for ink jet of the present invention, the polymer used for the colored fine particles is preferably blended in the ink in an amount of 0.5 to 50% by mass,
It is more preferable to add 0.5 to 30% by mass.

The blending amount of the blending polymer is 0.5% by mass.
If it is less than 50, the protection of the fluorescent coloring material is not sufficient,
If the content exceeds the mass%, the storage stability of the suspension as ink may deteriorate, or the printer head may be clogged due to thickening of the ink due to ink evaporation at the nozzle tip or aggregation of the suspension. It is preferably within the above range.

On the other hand, 1 part of the fluorescent coloring material is contained in the ink.
-30 mass% is preferable, and it is 1.5-25.
It is more preferable that the composition is blended by mass%. If the content of the fluorescent coloring material is less than 1% by mass, the print density will be insufficient, and 3
If it exceeds 0% by mass, the stability of the suspension with time decreases and the particle size tends to increase due to aggregation or the like.

The fluorescent color ink for ink jet according to claim 4 of the present invention comprises a suspension of a polymer in which water is used as a medium and in which the fluorescent colorant is encapsulated. Therefore, the suspension has a water-soluble organic solvent, and the suspension has a water-soluble organic solvent. Conventionally known various additives, for example, dispersants, antifoaming agents such as silicon, antifungal agents such as chloromethylphenol or chelating agents such as EDTA, oxygen absorbers such as sulfite may be contained. .

As the water-soluble organic solvent used in the present invention, alcohols (eg, methanol, ethanol,
Propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc., polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol) , Dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (for example, ethylene glycol monomethyl ether,
Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monomethyl ether Ethyl ether, triethylene glycol monobutyl ether,
Ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, Triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine,
Tetramethylpropylenediamine, etc., amides (eg, formamide, N, N-dimethylformamide,
N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1,3
-Dimethyl-2-imidazolidinone etc.), sulfoxides (eg dimethyl sulfoxide etc.), sulfones (eg sulfolane etc.), urea, acetonitrile, acetone and the like.

As the dispersant according to the present invention, a dispersant composed of a water-soluble polymer is preferable, and the following water-soluble resins are preferable from the viewpoint of ejection stability.

Styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid-acrylic acid copolymer, styrene-maleic acid copolymer, styrene-
Maleic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic acid copolymer , Vinylnaphthalene-maleic acid copolymers and the like.

The content of the water-soluble polymer with respect to the total amount of the ink is preferably 0.1 to 10% by mass, more preferably 0.3 to 10% by mass.

The average particle size of the dispersoid in the present invention is 50.
To 200 nm, more preferably 5
0 to 120 nm, and if the average particle size is less than 50 nm, it is difficult to form dispersed particles composed of a coloring material and a polymer.
If it exceeds 200 nm, the transparency of the ink and the vividness of the color deteriorate.

As a method for dispersing the pigment, a ball mill, a sand mill, an attritor, a roll mill, an agitator,
A Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, a paint shaker, etc. can be used.

In the present invention, a centrifugal separator or a filter is preferably used for the purpose of removing coarse particles of the pigment dispersion.

Surfactants preferably used in the fluorescent color ink for ink jet of the present invention include anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates and fatty acid salts, polyoxyethylene alkyl ethers, Examples thereof include nonionic surfactants such as polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, an anionic surfactant can be preferably used.

In addition to the above, an antiseptic, a fungicide, a pH adjusting agent, a viscosity adjusting agent and the like can be added to the fluorescent color ink for ink jet of the present invention as required.

[0069]

EXAMPLES Hereinafter, the ink jet ink of the present invention will be described in more detail with reference to Examples, but it goes without saying.
The present invention is not limited to this.

(Fabrication of Head) The head of the ink jet printer used in the present invention will be described with reference to FIGS.

FIG. 1 is a schematic perspective view showing a partial cross section of a head of an ink jet printer used in the present invention, and FIG. 2 is a schematic cross sectional view showing an example of an ink channel portion of the head of an ink jet printer used in the present invention. is there.

A lower substrate 1b and an upper substrate 1c made of lead zirconate titanate, which is a piezoelectric material, are bonded to each other with an adhesive 6 to form the same. The lower substrate 1b and the upper substrate 1c are polarized in opposite directions as indicated by arrows in FIG. A plurality of elongated grooves 2 are formed on the upper substrate 1c and the lower substrate 1b. As a result, a plurality of parallel partition walls 4 and grooves 2 are formed.

The electrode film 3 is provided on the inner surfaces of the plurality of grooves by vapor deposition. After attaching the electrode film 3 to the groove 2, a part of the upper surface of the substrate 1 is step-processed to form a step part 35.

The lid 8 is adhered to the upper surface of the partition 4 with the adhesive 6, and the sealing groove piece 25 is attached to the end surface of the partition 4 with the adhesive.

The surface of the electrode film 3 formed on both sides of the plurality of grooves is coated with an insulating film 17 such as parylene to form the insulating film 1.
The surface of No. 7 is hydrophilized by oxygen plasma treatment. By this hydrophilic treatment, bubbles are less likely to remain in the head, and the ejection stability is improved.

A nozzle plate 10 having a nozzle hole 11 on the end face of the groove 2 is adhered by the same adhesive 6 to form ink channels 9 in every other groove 2.

Nozzle holes are provided corresponding to each ink channel, and every other nozzle hole is provided corresponding to the groove 2.

A common groove 5 is carved in the upper portion of the lid 8 and a hole 12 is provided for communicating with each ink channel. Groove 2
Have every other nozzle hole 11 and communication hole 12. An upper plate 1 having an ink supply hole 15 on the lid 8
4 is adhered with an adhesive 6 so as to cover the upper part of the common groove 5.

The electrode films are connected to the lead wirings 7 exposed on the step 35 of the lid 8.

Ink is supplied from the ink supply hole 15 to fill the ink channels 9 formed in every other groove 2 arranged in parallel in FIGS. Ink is not supplied to the dummy grooves (air channels) 9'on both sides.

When an electric signal is sent to the lead line 7 and a drive voltage is applied between the electrode film of the ink channel 2a and the electrode films of the dummy grooves on both sides thereof so that the electric potential of the electrode film of the ink channel becomes high, ink is applied. The partition walls on both sides of the channel 2a are deformed inward, the ink channel contracts, and the ink is ejected as a small droplet. Subsequently, when the ink channel electrode film is grounded, the deformation disappears and the ink is sucked into the ink channel.

As the adhesive 6, a combination of the following epoxy resin and curing agent was used.

[0083]

[Chemical 1]

(Synthesis example 1, core-shell type colored fine particles according to the present invention) 4.6 g of polyvinyl butyrate (BL-S manufactured by Sekisui Chemical Co., Ltd., average degree of polymerization 350), 3 g and 45 g of fluorescent coloring materials shown in Table 1 The ethyl acetate of 1 was placed in a separable flask, the inside of the flask was replaced with N ₂ , and the mixture was stirred to completely dissolve it. 90 g of an aqueous solution containing 1.9 g of sodium lauryl sulfate was dropped and stirred, and then an ultrasonic disperser UH-150 was used.
It emulsified for 300 seconds using the mold (made by SMT). Then, ethyl acetate was removed under reduced pressure to obtain colored fine particles impregnated with the dye. 1.5 g of potassium persulfate was added and dissolved, and after heating to 80 ° C. using a heater, reaction was continued for 7 hours while further adding a mixed liquid of 1.5 g of styrene and 1.5 g of 2-hydroxyethyl methacrylate. Thus, a dispersion liquid of core-shell type colored fine particles was obtained. Add 20g of ethylene glycol and an appropriate amount of water to this solution, and add 120g.
An ink was prepared by finishing to g. The average particle size of the colored fine particles was 98 nm.

(Synthesis Example 2, Pigment Colored Fine Particles According to the Present Invention) Fluorescent pigment Lum finely dispersed with an average particle size of 98 nm
1.5 g of potassium persulfate was added to 900 ml of a dispersion containing 50 g of brilliant yellow to dissolve, and the mixture was heated to 80 ° C. using a heater, and then a mixture of 20 g of styrene and 20 g of 2-hydroxyethyl methacrylate was added dropwise. While reacting for 7 hours, a pigmented fine particle dispersion liquid having a shell structure was obtained.

99 ml of this liquid was sampled, 20 g of ethylene glycol and an appropriate amount of water were added to make 120 g, and an ink was prepared. The average particle size of the pigment coloring fine particles is 1
It was 10 nm.

(Synthesis Example 3, Comparative Uniform Colored Fine Particles)
4.6 g of polyvinyl butyral (Sekisui Chemical Co., Ltd. B
L-S, average degree of polymerization 350), 3 g of fluorescent color material described in Table 1.
And 45 g of ethyl acetate in a separable flask,
The inside of the flask was replaced with N ₂ gas and then stirred to completely dissolve it. Aqueous solution 9 containing 1.9 g of sodium lauryl sulfate
0 g was added dropwise and stirred, and then 30 using the ultrasonic disperser.
Emulsified for 0 seconds. Then, ethyl acetate was removed under reduced pressure to obtain a dispersion liquid of colored fine particles impregnated with the dye. Add 20g of ethylene glycol and an appropriate amount of water to this solution, and add 120g.
An ink was prepared by finishing to g. The average particle diameter of the colored fine particles was 104 nm.

(Synthesis Example 4, Core Shell Type Fluorescent Pigment Colored Fine Particles According to the Present Invention) Lumogen Brilliant
t Yellow 50g to polyvinyl butyral 10
g, 150 g of ethyl acetate, and dispersed using a sand grinder filled with 0.5 nm zirconia beads at a volume ratio of 50% until the average particle size becomes 60 nm, and the precipitate is removed with a centrifuge to obtain a dispersion liquid. Got This dispersion 1
2.5 g of polyvinyl butyral and 3 g of ethyl acetate
6 g was placed in a separable flask, the inside of the flask was replaced with N ₂ gas, and the mixture was stirred and mixed. 90 g of an aqueous solution containing 1.9 g of sodium lauryl sulfate was added dropwise, stirred and then emulsified for 300 seconds using the ultrasonic disperser. Then, ethyl acetate was removed under reduced pressure to obtain colored fine particles. To this, 1.5 g of potassium persulfate was added and dissolved, and after heating to 80 ° C. using a heater, a mixed solution of 1.5 g of styrene and 1.5 g of 2-hydroxyethyl methacrylate was added dropwise to 7 The reaction was carried out for a time to obtain a dispersion liquid of core-shell type colored fine particles. An ink was prepared by adding 20 g of ethylene glycol and an appropriate amount of water to this liquid to make 120 g. The average particle size of the colored fine particles was 200 nm.

Each of the colored fine particles synthesized by the above method was used in an amount of 2% by weight of fluorescent coloring material, 10% by weight of ethylene glycol,
Glycerin was adjusted to 10% by mass and further 5 μm
The ink was filtered using the filter No. 1 to remove dust and coarse particles to obtain an inkjet ink.

[Preparation of Ink Other than Fluorescent Color] (Yellow Pigment Dispersion) C.I. I. Pigment Yellow 95 g Demol C (manufactured by Kao Corporation) 65 g Ethylene glycol 100 g Ion-exchanged water 120 g are mixed, and 0.5 mm zirconia beads are mixed at a volume ratio of 5
It was dispersed using a sand grinder filled with 0% to obtain a yellow pigment dispersion liquid, and a sediment was removed by a centrifuge.

(Magenta Pigment Dispersion) C.I. I. Pigment Red 122 105 g Acrylic styrene-based resin (John Cryl 61, manufactured by Johnson Co.) 60 g Glycerin 100 g Ion-exchanged water 130 g are mixed, and 0.5 mm zirconia beads are mixed at a volume ratio of 5
Dispersion was carried out using a sand grinder filled with 0% to obtain a magenta pigment dispersion liquid, and sediment was removed by a centrifuge.

(Cyan Pigment Dispersion) C.I. I. Pigment Blue 15: 3 100 g Demol C (manufactured by Kao Corporation) 63 g Diethylene glycol 100 g Ion-exchanged water 125 g were mixed, and 0.5 mm zirconia beads were mixed at a volume ratio of 5
A 0% filled sand grinder was used for dispersion to obtain a cyan pigment dispersion. The sediment of the cyan pigment dispersion was removed with a centrifuge.

(Carbon Black Dispersion) Toka Black # 8500 (manufactured by Tokai Carbon Co., Ltd.) 120 g John Cryl 62 (manufactured by Johnson Polymer Co., Ltd.) 59 g Rebenol WX (manufactured by Kao Corporation) 3 g Diethylene glycol 100 g Ion-exchanged water 300 g And 0.5 mm zirconia beads at a volume ratio of 5
Dispersion was carried out using a sand grinder filled with 0% to obtain a black pigment dispersion. The sediment of the cyan pigment dispersion was removed with a centrifuge.

(Yellow Ink) Yellow pigment dispersion 110 g Nipol LX844 (manufactured by Nippon Zeon Co., Ltd .; solid content 40%) 50 g Ethylene glycol 200 g Propylene ethylene glycol 150 g Olphin 1010 (manufactured by Nissin Chemical Co., Ltd.) 4 g Proxel GXL ( Zeneca Co., Ltd.) 2 g Dioctyl sulfo succinate 0.1 g Sodium chloride 0.6 g With a formulation made up to 1000 g with ion-exchanged water and stirred thoroughly, it was passed through a Millipore filter with a pore size of 1 μm twice. , Got the ink. The average particle size of the pigment is 1
It was 22 nm. The particle size was measured by Zetasizer 1000 manufactured by Malvern Instruments.

(Magenta ink) Magenta pigment dispersion liquid 100 g Nipol SX1105 (manufactured by Nippon Zeon Co., Ltd .; solid content 45%) 56 g Ethylene glycol 150 g Diethylene glycol 150 g Perex OT-P 4 g Proxel GXL (previously mentioned) 2 g Sodium hydroxide 0. 1 g of sodium dioctylsulfosuccinate 0.1 g of potassium nitrate 1.8 g was made up to 1000 g with ion-exchanged water, thoroughly stirred, and then passed twice through a Millipore filter having a pore size of 1 μm to obtain an ink. The average particle size of the obtained pigment was 85 nm.

(Cyan Ink) Cyan Pigment Dispersion Liquid 110 g Takelac W-605 (manufactured by Takeda Pharmaceutical Co., Ltd .; solid content: 30%) 267 g Ethylene glycol 100 g Diethylene glycol 140 g Emulgen 913 4 g Proxel GXL (previously mentioned) 2 g Dioctylsulfosuccinate sodium An ink was obtained by using a formulation consisting of 0.1 g sodium chloride 0.8 g potassium chloride 0.3 g to make 1000 g with ion-exchanged water, stirring thoroughly, and then passing through a Millipore filter filter having a pore size of 1 μm twice. The average particle size of the obtained pigment was 105 nm.

(Black Ink) Carbon Black Dispersion 160 g Ethylene Glycol 150 g Triethylene Glycol Monobutyl Ether 100 g Perex OT-P (manufactured by Kao Corporation) 2 g Proxel GXL (above) 2 g of ion-exchanged water to 1000 g. After finishing and stirring sufficiently, the mixture was passed twice through a Millipore filter having a pore size of 1 μm to obtain an ink. The average particle size of the obtained pigment was 44 nm.

By combining the yellow ink, magenta ink, cyan ink, and black ink described above with the inks shown in Table 1, an inkjet printer equipped with an inkjet printer head shown in FIGS. Images were recorded at a discharge frequency of 6 picoliters and a drive frequency of 30 kHz.

(Evaluation of Ink) An image printed on a white background with a fluorescent color ink is observed under a fluorescent lamp, and the vividness of the fluorescent color is clearly brighter than ◯: yellow, magenta and cyan. Δ: yellow, magenta, Slightly brighter than cyan x: Yellow, magenta, cyan or less The evaluation criteria were as follows.

(Color Reproduction of Photographic Image) When the fluorescent color inks are overlaid on the yellow, magenta, and cyan images, the influence on the colors other than the fluorescent color is ◯: Saturation of yellow, magenta, and cyan is hardly reduced. Evaluation was made based on the criteria that: Saturation is reduced in one or two colors of yellow, magenta, and cyan. X: Saturation of yellow, magenta, and cyan are all reduced.

(Evaluation of light resistance) Regarding light resistance, a low temperature Xe weather meter XL75 (manufactured by Gas Testing Machine Co., Ltd.) was used.
The density change was measured by using X-Rite900 (manufactured by Nippon Lithographic Equipment Co., Ltd.), and the density of the portion recorded with the fluorescent ink was measured. With residual concentration above (acceptable level) △: After 1 week, with residual concentration of 30% or more and less than 50% from original concentration ×: After 1 week With residual concentration of 30% or less from original concentration It was evaluated according to the evaluation criteria of the ones (impossible level).

(Ejection stability) Under the recording conditions of the above printer, the emission stability is ◯: No continuous ejection of nozzles for 30 minutes or longer (allowable level) Δ: Continuous ejection of 10 minutes or more, 30 minutes When the nozzle deficiency occurred at less than x: The nozzle deficiency occurred at 10 minutes or less after continuous emission (permissible level).

The above results are shown in Table 1.

[0104]

[Table 1]

From Table 1, it can be seen that the fluorescent color ink for inkjet of the present invention is superior in the vividness of the fluorescent color, the color reproduction of the photographic image, the image light fastness and the emission stability as compared with the comparative sample.

[0106]

According to the present invention, it is possible to provide an ink jet ink having a bright fluorescent color, good color reproduction, and excellent light resistance and emission stability.

[Brief description of drawings]

FIG. 1 is a schematic perspective view having a partial cross section of a head of an inkjet printer used in the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of an ink channel of a head of an inkjet printer used in the present invention.

[Explanation of symbols]

1 substrate 2 grooves 2a ink channel 3 electrode film 6 adhesive 8 lid 9 ink channels 9'dummy groove 14 Upper plate 15 Ink supply hole

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA04 EA13 FC01 FC02                 2H086 BA52 BA53 BA55 BA59 BA60                 4J039 AD06 AD07 AD10 AD17 AE05                       BA12 BE01 BE02 BE07 BE12                       CA06 EA15 EA16 EA17 EA19                       EA28 EA35 EA44 GA24

Claims (8)

[Claims] 1. An ink-jet characterized in that a core contains a fluorescent coloring material and a polymer, and has a dispersoid having a shell made of a polymer having a hydrophilic group formed on the outside thereof, a water-soluble organic solvent, and water. Fluorescent ink for use. 2. The fluorescent color ink for inkjet according to claim 1, wherein the fluorescent color material is an oil-soluble dye. 3. The inkjet fluorescent color ink according to claim 1, wherein the fluorescent color material is a pigment. 4. A fluorescent color ink for inkjet, comprising a dispersoid in which a fluorescent pigment as a fluorescent colorant and a polymer are mixed, and a dispersion medium composed of water and a water-soluble organic solvent. 5. The average particle size of the dispersoid is 50 to 200.
nm is 1 nm, The claim 1 characterized by the above-mentioned.
The fluorescent color ink for inkjet according to the item. 6. The average particle size of the dispersoid is 50 to 120.
The fluorescent color ink for inkjet according to claim 5, wherein the fluorescent color ink is nm. 7. An inkjet fluorescent color ink set comprising a yellow ink, a magenta ink, a cyan ink, a black ink, and the fluorescent color ink according to claim 1. Description: 8. The inkjet fluorescent color ink set according to claim 7, wherein the yellow ink, the magenta ink, the cyan ink, and the black ink are pigment inks.