JP2000160072A - Recording ink - Google Patents

Abstract

(57) Abstract: The present invention provides an aqueous ink jet recording ink capable of obtaining a uniform image having high light resistance as compared with a conventional ink jet recording ink and hardly causing problems such as clogging and reliability. It is intended to provide. SOLUTION: A colorant which disperses or dissolves in water, a UV absorber monomer having a vinyl group and / or a light stabilizer monomer having a vinyl group, which is mainly composed of water and a water-soluble organic solvent, is constituted as a copolymerization component. A recording ink comprising a water-soluble resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink suitable for recording, particularly to an ink composition for ink jet recording capable of forming an image having excellent light fastness.

[0002]

2. Description of the Related Art An ink jet recording method in which a liquid ink is ejected from a nozzle to record an image is capable of printing on plain paper, easy to cope with colorization, noise during driving, and consumption. Due to low power and the like, printers for outputting documents and images created by computers have been rapidly spreading in recent years. Recent advances in inkjet recording technology have made it possible to obtain high-quality images at the same level as photographs.However, the output images have been used in a wide variety of applications, and can be stored for long periods in an environment exposed to light or outdoors. In some cases, it is used.

In order to satisfy the required light fastness of a recorded image at that time, various measures have been taken for a coloring agent to be used. Ink for ink jet recording, in addition to a colorant and a medium for dissolving or dispersing the colorant, various additives are further added as necessary, and an anti-fading agent is added to improve the light fastness of the recorded image. There is a method. For example, JP-A-05-239389 discloses a method of adding a hindered amine-based or benzophenone-based discoloration inhibitor to a dye-based aqueous ink.

Further, JP-A-09-132742 and JP-A-09-235500 disclose a method in which a diluent containing a hindered amine-based, benzotriazole-based, or benzophenone-based fading inhibitor is mixed with ink at the time of ejection. I have. However, many of such anti-fading agents have low solubility in water-soluble inks, and even when dissolved in ink, there is a limit to the compatibility with other components, and the dispersion on the recording material is uneven and sufficient. There were drawbacks such as the inability to obtain light fastness and the clogging of nozzles.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new ink composition which can solve the above-mentioned drawbacks of the conventional inks for ink jet recording. That is, an object of the present invention is to provide a water-based inkjet recording ink which can provide a uniform image having high light resistance as compared with a conventional inkjet recording ink and hardly cause problems such as clogging and reliability.

[0006]

Means for Solving the Problems In order to solve the above-mentioned technical problems, the present inventors have proposed a method of using an ultraviolet absorbent monomer having a vinyl group and / or a light stabilizer monomer having a vinyl group in a recording ink. The inventors have found that it is effective to include a water-soluble resin constituted as a copolymer component, and have reached the present invention.

Most of the conventional ultraviolet absorbers and light stabilizers used for improving the light fastness of ink are insoluble in water and difficult to be contained in the ink. The use of the UV absorber had almost no effect. On the other hand, the ink of the present invention containing a water-soluble resin comprising the ultraviolet absorbent monomer having a vinyl group and / or the light stabilizer monomer having a vinyl group is formed by the ink. This is very effective because the problem of poor light fastness, particularly in the case of an ink using a dye as a colorant, is solved because the light fastness of an image is improved.

In the present invention, since the ultraviolet absorber and the light stabilizer are incorporated as a constituent part of the water-soluble resin and the emulsion resin, the originally water-insoluble ultraviolet absorber and the light stabilizer monomer are used. Since it becomes a water-soluble resin without impairing the ultraviolet absorbing ability and the light stabilizing ability, the function can be sufficiently exhibited in the water-soluble ink. In addition, since it is added as a water-soluble resin, problems such as clogging of nozzles, unevenness of a recorded image, and deterioration of ink transparency do not occur.

The UV-absorbing monomer having a vinyl group represented by the formulas (1) to (4) used in the present invention is preferably at least one of the following formulas (9) to (12). At least one selected from the group consisting of benzotriazole, benzophenone, cyanoacrylate and salicylic acid is exemplified.

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As the light stabilizer monomer having a vinyl group used in the present invention, at least one monomer represented by the following formula (5) is preferable, and one example thereof is a hindered amine represented by the following formula (13). And the like.

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The ultraviolet absorbent monomer having at least one vinyl group represented by the above formulas (1) to (4) and / or
Alternatively, the water-soluble resin containing at least one light stabilizer monomer having a vinyl group represented by the formula (5) as a copolymer component includes polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, and acetic acid. Vinyl-acrylic acid ester copolymer, acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid-alkyl acrylate copolymer,
Styrene-methacrylic acid-alkyl acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-alkyl acrylate copolymer, styrene-maleic acid copolymer, vinylnaphthalene- Maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl-ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-
At least one kind selected from the group consisting of acrylic acid copolymers, cyclodextrins and β-cyclodextrins is included.

The average molecular weight of the water-soluble resin is preferably from 3,000 to 50,000 in consideration of the discharge properties of the ink-jet ink and the function of dispersing the pigment. Further, the water-soluble resin can be used in the form of particles, the particle size of which is
Considering the diameter (nozzle) of the discharge port of the head, etc., 150
nm or less is preferred. However, the water-soluble resin may be used in a linear shape or another shape other than the particle shape. Further, if the acid value of the water-soluble resin exceeds 7, an unreacted hydroxyl group remains as it is, so that the acid value is preferably 7 or less. Further, in consideration of the abrasion resistance of the cured film of the water-soluble resin, the minimum film-forming temperature of the water-soluble resin is preferably room temperature or room temperature or lower, that is, 25 ° C. or lower, and more preferably about 7 ° C. or lower.

[0013] The cleavage of chemical species photoexcited by ultraviolet light produces various radicals, which are one of the causes of degradation of the dye. Light stabilizers such as hindered amine compounds effectively trap these radicals. However, when used in combination with an ultraviolet absorber that cuts off the cause of the series of reactions, the light resistance can be further improved.

Therefore, also in the present invention, the combined use of an ultraviolet absorber and a light stabilizer as a water-soluble resin monomer and as a component of a water-soluble resin results in a synergistic effect, so that a smaller amount than when each is used alone. Greater effects can be obtained with the additives. The water-soluble resin,
It is preferable that the content is 0.1 to 20% by weight in the ink.

The ink composition of the present invention contains, as essential components, a dye and / or pigment, a wetting agent, and water in addition to the water-soluble resin. Hereinafter, the components of the ink composition of the present invention will be specifically described.

Specific examples of the pigment used in the present invention include the following. These pigments may be used as a mixture of a plurality of types, or may be used as a mixture with other dyes such as dyes. These colorants are added in amounts that do not impair the effects of the present invention. Examples of organic pigments include azo, phthalocyanine, anthraquinone, dioxazine, indico, thioindico, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigments, and carbon black. The pigment has a particle size of 0.01 to 0.15.
It is preferably used as a particle having a size of μm.

Examples of the inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, navy blue, cadmium red, chrome yellow, and metal powder. Among them, carbon black and carbon black modified such as surface hydrophilicity are preferable as black inks particularly preferable for the color image formation of the present invention.
Azo yellow C.I. I. Pigment Yellow 13, 17, 174, etc., quinacridone-based Pigment Red 122 and azo-based Pigment Red 184 are used as magenta, and copper phthalocyanine and metal-free phthalocyanine are used as cyan. Further, the particle size of these pigments is preferably used at 0.01 to 0.15 μm,
When the thickness is less than 0.01 μm, the hiding power is reduced and the concentration is low, and the light fastness is reduced, so that the light fastness of the ink when mixed with a polymer dye is equivalent to that of a conventional dye. On the other hand, if the thickness is 0.15 μm or more, clogging of the head and clogging of the filter in the printer occurs, and it is impossible to obtain ejection stability.

Examples of the pigment dispersant include a pigment dispersant having a hydrophilic portion and a hydrophobic portion. Specific examples of the pigment dispersant include the following.
The water-soluble resin can also be used as a pigment dispersant. When this water-soluble resin is used as a pigment dispersant, it is not necessary to use a pigment dispersant as described below. Hydrophilic polymers (a) Natural polymers Plant gums such as gum arabic, gum tragan, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, algalic acid, carrageenan, agar, etc. Molecules; animal macromolecules such as gelatin, casein, albumin, and collagen; and microbial macromolecules such as xanthene gum and dextran.

(B) Semi-synthetic polymers Cellulose polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose; starch polymers such as sodium starch glycolate and sodium starch phosphate; alginic acid Seaweed polymers such as sodium and propylene glycol alginate.

(C) Pure synthetic polymers Vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyvinyl methyl ether, non-crosslinked polyacrylamides, polyacrylic acids and alkali metal salts thereof, and acrylics such as water-soluble styrene acrylic resins resin,
Water-soluble styrene maleate resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleate resin, polyvinyl pyrrolidone, polyvinyl alcohol, β
An alkali metal salt of a naphthalenesulfonic acid formalin condensate; a polymer compound having a salt of a cationic functional group such as a quaternary ammonium or an amino group in a side chain; and a natural polymer compound such as a ceramic.

Dyes The water-soluble dyes used in the present invention include those classified into acid dyes, direct dyes, basic dyes, reactive dyes and edible dyes in the color index and having excellent water resistance and light resistance. Used. These dyes may be used by mixing a plurality of types, or may be used by mixing with other dyes such as pigments as necessary. These coloring agents are added in a range that does not impair the effects of the present invention.

(A) As acid dyes and food dyes, C.I. I. Acid Yellow 17,23,42,4
4,79,142 C.I. I. Acid Red 1,8,13,14,1
8, 26, 27, 35, 37, 42, 52, 82, 8
7, 89, 92, 97, 106, 111, 114, 11
5,134,186,249,254,289 C.I. I. Acid Blue 9,29,45,92,2
49 C.I. I. Acid Black 1,2,7,24,2
6,94 C.I. I. Food Yellow 3,4 C.I. I. Food Red 7, 9, 14 C.I. I. Food black 1,2

(B) As a direct dye, C.I. I. Direct Yellow 1,12,24,2
6,33,44,50,86,120,132,14
2,144 C.I. I. Direct Red 1,4,9,13,1
7, 20, 28, 31, 39, 80, 81, 83, 8
9,225,227 C.I. I. Direct orange 26,29,62,1
02 C.I. I. Direct Blue 1,2,6,15,2
2,25,71,76,79,86,87,90,9
8,163,165,199,202 C.I. I. Direct Black 19,22,32,3
8, 51, 56, 71, 74, 75, 77, 154, 1
68,171

(C) As a basic dye, C.I. I. Basic Yellow 1,2,11,13,
14, 15, 19, 21, 23, 24, 25, 28, 2
9, 32, 36, 40, 41, 45, 49, 51, 5
3,63,64,65,67,70,73,77,8
7, 91 C.I. I. Basic Red 2,12,13,14,
15, 18, 22, 23, 24, 27, 29, 35, 3
6,38,39,46,49,51,52,54,5
9, 68, 69, 70, 73, 78, 82, 102, 1
04, 109, 112 C.I. I. Basic Blue 1,3,5,7,9,2
1,22,26,35,41,45,47,54,6
2,65,66,67,69,75,77,78,8
9, 92, 93, 105, 117, 120, 122, 1
24, 129, 137, 141, 147, 155 C.I. I. Basic Black 2,8

(D) As a reactive dye, C.I. I. Reactive Black 3,4,7,11,
12, 17 C.I. I. Reactive Yellow 1,5,11,1
3,14,20,21,22,25,40,47,5
1, 55, 65, 67 C.I. I. Reactive Red 1,14,17,2
5,26,32,37,44,46,55,60,6
6, 74, 79, 96, 97 C.I. I. Reactive Blue 1,2,7,14,1
5,23,32,35,38,41,63,80,95
Etc. can be used.

In the recording ink of the present invention, a penetrant (wetting agent) is used in order to improve the wettability between the ink and the paper surface and to increase the speed of penetration of the ink into the paper. As the penetrant (wetting agent), those represented by the following formulas (I) to (IV) are preferable. That is, a polyoxyethylene alkyl phenyl ether surfactant of the following formula (I), an acetylene glycol surfactant of the formula (II), a polyoxyethylene alkyl ether surfactant of the following formula (III), and a compound of the formula (IV) The polyoxyethylene polyoxypropylene alkyl ether surfactant of the type) can reduce the surface tension of the ink to 50 mJ / m ² , so that the wettability between the ink and the paper surface is improved, and the penetration of the ink into the paper is improved. By increasing the speed and solubilizing action of the polyoxyethylene chain, the dispersion stability of the colorant is improved, and image deterioration is extremely small.

[0027]

Embedded image (R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k: 5 to 20)

[0028]

Embedded image (M and n are 0 to 40)

[0029]

Embedded image (R is a hydrocarbon chain having 6 to 14 carbon atoms, m, n: 20 or less)

These activators (I), (II), (III),
By adding urea and urea derivatives such as hydroxyethyl urea and dihydroxyethyl urea in addition to (IV), the interaction between the water-soluble resin and the nonionic activator is weakened and the association of the water-soluble resin is relaxed to improve the permeability. And improved discharge stability and long-term storage stability. It is preferable to use the added amount of these urea derivatives between 0.1% and 5%. If it is 0.1% or less, there is no effect, and if it is 5% or more, it may affect the viscosity change at the time of moisture evaporation.

In the ink composition of the present invention, for the purpose of adjusting the surface tension of the ink composition, the above formulas (I) to (I)
In addition to the compounds of V), for example, polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether Alkyl and aryl ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine surfactants, and lower alcohols such as ethanol and 2-propanol can be used. Butyl ether is preferred.

Although the ink of the present invention uses water as a liquid medium, it is intended to obtain desired physical properties of the ink, to prevent drying of the ink, and to improve the dissolution stability. For example, the following water-soluble organic solvents are used. These water-soluble organic solvents may be used as a mixture of two or more.

The following are specific examples of the water-soluble organic solvent. Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-
Polyhydric alcohols such as butanetriol, 1,2,3-butanetriol and petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether And polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; N-methyl-2-pyrrolidone and N-hydroxyethyl-2- Pyrrolidone, 2-pyrrolidone, 1,
Nitrogen-containing heterocyclic compounds such as 3-dimethylimidazolidinone and ε-caprolactam; amides such as formamide, N-methylformamide and N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine , Amines such as triethylamine and the like; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol; and cyclic esters such as propylene carbonate, ethylene carbonate and γ-butyrolactone.

Among these organic solvents, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2 , 4-butanetriol, 1,2,3-butanetriol, petriol, thiodiethanol, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone Is preferred. These have an excellent effect on solubility and prevention of poor jet characteristics due to water evaporation. Particularly, a pyrrolidone derivative such as N-hydroxyethyl-2-pyrrolidone is preferable because the dispersion stability of the surfactant (I) can be obtained. The surface tension in the present invention is an index indicating permeability to paper, and particularly indicates a dynamic surface tension in a short time of 1 second or less after the surface is formed, and is different from a static surface tension measured in a saturation time. . As a measuring method,
Any method can be used as long as it can measure a dynamic surface tension of 1 second or less by a conventionally known method described in, for example, Japanese Patent No. 31237 or the like, but in the present invention, it was measured using a Wilhelmy type hanging plate type surface tensiometer. The value of surface tension is 50 mN /
m or less, more preferably 40 mN / m or less, to obtain excellent drying properties.

In the ink of the present invention, conventionally known additives can be added in addition to the coloring agent and the solvent.
For example, preservatives and fungicides include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1
-Sodium oxide, sodium benzoate, sodium pentachlorophenol, benzisothiazoline-
3-ones and the like can be used in the present invention.

As the pH adjuster, any substance can be used as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared. Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium. Examples include hydroxides, carbonates of alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate.

Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like. As a rust inhibitor, for example,
Acid sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite,
Examples include pentaerythritol tetranitrate and dicyclohexylammonium nitrite. As an anti-clogging agent,
For example, there are urea derivatives such as urea and hydroxyethyl urea. In addition, a water-soluble ultraviolet absorber and a water-soluble infrared absorber can be added according to the purpose.

Method for Synthesizing Water-Soluble Resin Experimental Example 1 Using a 300 ml five-necked flask equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet tube, and ceramic rubber (sample sampling port), polyoxyethylene nonylphenyl was used. Ether (Nonipol 400, manufactured by Sanyo Chemical Co., Ltd.) was used as a surfactant and an initiator (reducing agent), and cerium sulfate (I
V) Compound 6 using ammonium as an initiator (oxidizing agent)
Emulsion polymerization of [trade name: RUVA-93 manufactured by Otsuka Chemical Co., Ltd.] and acrylic acid was performed at 25.0 ± 0.2 ° C. First,
Aqueous solution of polyoxyethylene nonyl phenyl ether 2
00ml, compound IV 10g and acrylic acid monomer 10g
Is added, and the system is replaced with nitrogen gas while stirring at 250 rpm. 10m cerium (IV) salt aqueous solution
Add l. At this time, ammonium nitrate was added,
Is adjusted from 1.3 to 1.4. The concentration of each reagent in the system was [E] = 9.84 × 10 ⁻³ mol ⁻¹ , [C]
e ⁴⁺ ] = 0.984 × 10 ⁻³ mol ⁻¹ , [NH ₄ NO ₃ ]
= 58.8 × 10 ⁻³ mol ⁻¹ . After stirring for 8 hours, the resulting emulsion was agglomerated and dried. The yield was 80%. The obtained water-soluble resin is referred to as Compound 13.

Experimental Example 2 300 parts of ion-exchanged water was placed in a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooling tube, boiled for 30 minutes, deaerated, and cooled to room temperature under nitrogen. Polyoxyethylene nonyl phenyl ether (Nonipol 400,
Sanyo Chemical Industries (Ltd.) 12 parts, FeSO ₄ · 7H ₂ O0.0
5 parts and 0.50 parts of Rongalite are added. After dissolution,
200 parts of a vinyl acetate-methanol (3: 1) mixture deaerated by heating at 60 ° C. under nitrogen and Compound 11 (trade name: ADK STAB LA-82, manufactured by Asahi Denka Co., Ltd.) or Compound 12
[Product name ADK STAB LA-87 manufactured by Asahi Denka Co., Ltd.]
Add 00 parts and stir at room temperature for 30 minutes. Then -20
C. and cooled with degassed ion-exchanged water.
% Hydrogen peroxide solution is continuously added at 12 parts per hour to initiate polymerization. The polymerization system is sealed with nitrogen gas to prevent oxygen from entering during polymerization. After polymerization for 2 hours, the resulting emulsion is poured into 3000 parts of methanol in which 0.5 part of hydroquinone monomethyl ether is dissolved. After dissolution, unreacted monomers are distilled off under reduced pressure to obtain a methanol solution of the resulting emulsion. The polymerization rate was 85%, and the intrinsic viscosity at 30 ° C. of the water-soluble resin (compound 18) or (compound 19) obtained by alkali-saponification and redissolution of this was 3.62 dlg ⁻¹ in acetone. . Similarly, emulsions of compounds 13 to 19 were synthesized using monomers of compounds 6 to 12.

[0040]

[Table 1]

[0041]

[Table 2]

Examples of the present invention and comparative examples are shown below.

Example 1 First, carbon black was dispersed with an ultrasonic homogenizer in the presence of a dispersant, and a composition having the following formulation was stirred and dissolved using a dispersion having a particle size of 0.1 μm or less. And
The pH was adjusted to 8.5 with a 10% aqueous solution of lithium hydroxide, and this was filtered through a 0.45 μm Teflon filter to prepare Ink 1. Carbon black (surface-hydrophilized by plasma) 5% by weight Water-soluble resin [Compound 13] 3% by weight Glycerol 10% by weight N-hydroxyethylpyrrolidone 5% by weight Triethylene glycol monobutyl ether 5% by weight Surface activity Agent (I) (R = C ₆ H ₁₃ , k = 18) 0.5% by weight Deionized water

Example 2 An ink 2 was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 8.8 with sodium hydroxide. C. I. Pigment Yellow 17 1.2% by weight Water-soluble resin [Compound 14] 5% by weight Glycerol 10% by weight 1,2,6-hexanetriol 4% by weight 1,5-pentanediol 8% by weight Diethylene glycol monobutyl ether 5% by weight N- Methyl-2-pyrrolidone 2% by weight Surfactant (II) (m = 10, n = 10) 1.2% by weight Sodium alginate 0.05% by weight Urea 5% by weight Deionized water

Example 3 The procedure of Example 1 was repeated, except that the following composition was used.
Was adjusted to 8.5 with lithium hydroxide to prepare Ink 3. C. I. Pigment Red 122 1% by weight Water-soluble resin [Compound 15] 3% by weight Glycerol 10% by weight Diethylene glycol 5% by weight N-hydroxyethylpyrrolidone 3% by weight Triethylene glycol monobutyl ether 5% by weight Surfactant (I) (R = C _{9 H 19, k = 12)} 1 wt% ion-exchanged water Balance

Example 4 The procedure of Example 1 was repeated, except that the following composition was used.
Was adjusted to 9.5 with lithium hydroxide to prepare Ink 4. Copper phthalocyanine 1% by weight Water-soluble resin [compound 16] 4% by weight Glycerol 5% by weight Ethylene glycol 3% by weight 1,5-pentanediol 5% by weight 2-pyrrolidone 2% by weight Triethylene glycol monobutyl ether 5% by weight Surfactant (IV) (m = n = 20) 0.8% by weight Urea 5% by weight Deionized water

Example 5 The procedure of Example 1 was repeated except that the following composition was used.
Was adjusted to 7.8 with sodium hydroxide to prepare Ink 5. Rhodamine B aluminum lake pigment 1.2% by weight Water-soluble resin [Compound 17] 5% by weight Glycerol 10% by weight Triethylene glycol 5% by weight Petriol 5% by weight N-methyl-2-pyrrolidone 3% by weight Diethylene glycol monobutyl ether 5% by weight % Surfactant (III) [R = (C ₆ H ₁₂ ) ₂ CH-, n = 12] 1% by weight Hydroxyethyl urea 5% by weight Deionized water

Example 6 The procedure of Example 1 was repeated, except that the following composition was used.
Was adjusted to 8 with lithium hydroxide to prepare Ink 6. Metal-free phthalocyanine 1.5% by weight Water-soluble resin [compound 18] 5% by weight Glycerol 10% by weight 2-pyrrolidone 2% by weight Diethylene glycol monobutyl ether 5% by weight Surfactant (II) (m = n = 20) 1% by weight Surfactant (II) (m = n = 10) 1% by weight Hydroxyethyl urea 5% by weight Deionized water

Example 7 The procedure of Example 1 was repeated, except that the following composition was used.
Was adjusted to 8 with lithium hydroxide to prepare ink 7. C. I. Pigment Red 122 1.2% by weight Water-soluble resin [compound 19] 4% by weight Glycerol 10% by weight N-methyl-2-pyrrolidone 4% by weight 1,5-pentanediol 5% by weight Triethylene glycol monobutyl ether 5% by weight Interface Activator (IV) (R = lauryl group, m = 18, n = 6) 1.5% by weight Deionized water

Comparative Example 1 The procedure of Example 1 was repeated, except that the water-soluble resin [Compound 13] was changed to a low-molecular weight water-soluble benzotriazole-based ultraviolet absorber [Compound 20: Biosorb 520 Kyodo Yakuhin Co., Ltd.]. Ink 8 was obtained.

Comparative Example 2 In Example 2, the water-soluble resin [Compound 14] was replaced with a low-molecular-weight water-soluble benzophenone-based UV absorber [Compound 2
1: Viosorb 100 Kyodo Yakuhin Co., Ltd.], except that ink 9 was used.

Comparative Example 3 Ink 10 was prepared in the same manner as in Example 3 except that the water-soluble resin [Compound 15] was changed to a styrene-methacrylic acid resin containing no UV absorber monomer.

Comparative Example 4 The procedure of Example 4 was repeated, except that the water-soluble resin [compound 16] was changed to a low-molecular-weight water-soluble cyanoacrylate-based ultraviolet absorbent [compound 22: Biosorb 910 Kyodo Yakuhin Co., Ltd.]. Ink 11 was obtained.

Comparative Example 5 In Example 5, the water-soluble resin [Compound 17] was replaced with a low-molecular-weight water-soluble salicylic acid ultraviolet absorber [Compound 23: Vio
sorb90 Kyodo Yakuhin Co., Ltd.].

Comparative Example 6 Example 6 was repeated except that the water-soluble resin [compound 18] was changed to a low molecular weight water-soluble hindered amine light stabilizer [compound 24: ADK STAB LA-77 Asahi Denka Kogyo KK]. In the same manner, ink 13 was obtained.

Comparative Example 7 An ink 14 was prepared in the same manner as in Example 7 except that the water-soluble resin [Compound 19] was omitted.

Embedded image

Next, the above Examples 1 to 7 and Comparative Examples 1 to
7 was subjected to the following test. 1) Image clarity Nozzle system of thermal inkjet system 45 μm, 30
Nozzle diameter 33 using inkjet printer having 0 dpi nozzle and laminated PZT for pressurizing liquid chamber flow path
Printing was performed using an inkjet printer having a nozzle of 128 μm and 128 dpi, and bleeding at the boundary of the two-color superposed portion, image bleeding, color tone, and density were visually judged comprehensively. The color development during OHP projection was also evaluated. The printing paper was printed on three types of commercially available recycled paper, high quality paper and bond paper.

2) Image Water Resistance The image sample was immersed in water at 30 ° C. for 1 minute, and the change in image density before and after the treatment was measured with a Macbeth densitometer. I asked.

(Equation 1) In any of the papers, と な っ indicates less than 10%, Δ indicates less than 30%, and X indicates 30% or more. 3) Light fastness of the image The image sample was irradiated with a xenon fade meter at a black panel temperature of 63 ° C. for 3 hours, and the change in image density before and after the treatment was measured with a Macbeth densitometer. %).

(Equation 2) In any of the papers, the case of 5% or less was evaluated as ○, the case of less than 30% as Δ, and the case of 30% or more as x. 4) Drying of Image The filter paper was pressed against the image after printing under certain conditions, and the time until the ink stopped transferring to the filter paper was measured. If any of the papers dried within 10 seconds, it was judged as "good". Anything above that is marked as x.

5) Storage stability Each ink was placed in a polyethylene container and stored at -20 ° C, 5 ° C,
The samples were stored at 20 ° C. and 70 ° C. for three months under the respective conditions, and the surface tension, viscosity, and the presence or absence of precipitates after storage were examined. No change in physical properties and the like was observed regardless of the conditions of storage. 6) Reliability at the time of printing pause Using a printer having a head driven by PZT having a nozzle diameter of 30 μm and 128 dpi, using a printer having a cap, cleaning, etc., during operation, it is examined how much printing can be resumed even after the printing is paused. The results of evaluating the reliability of whether the ejection direction is shifted or the weight of the ejected droplet changes in only a short time are shown in the table. Excellent ◎,
No problem ○, small change in drop weight, small bending △, noticeable clogging ×

[0060]

[Table 3]

[0061]

[Table 4]

Hereinafter, embodiments of the present invention will be described. 1. A colorant that disperses or dissolves in water, composed mainly of water and a water-soluble organic solvent, and composed of an ultraviolet absorber monomer having a vinyl group and / or a light stabilizer monomer having a vinyl group as a copolymerization component. A recording ink comprising a water-soluble resin. 2. The water-soluble resin is an ultraviolet absorber monomer having at least one vinyl group represented by formulas (1) to (4) and / or a light stabilizer monomer having at least one vinyl group represented by formula (5). The recording ink according to 1 above, comprising: 3. 0.1-20% by weight of water-soluble resin in water-soluble ink
The recording ink according to any one of the above items 1 to 2, which is contained. 4. The recording ink according to any one of the above 1 to 3, wherein the ultraviolet absorber having a vinyl group is at least one selected from the group consisting of a benzotriazole type, a benzophenone type, a cyanoacrylate type, and a salicylic acid type. 5. The recording ink according to claim 1, wherein the light stabilizer monomer having a vinyl group is a hindered amine type. 6. The recording ink according to any one of the above items 1 to 5, wherein the ultraviolet absorbent monomer having a vinyl group and / or the light stabilizer monomer having a vinyl group is contained in an amount of 1 to 20% by weight of the water-soluble resin. 7. As the copolymerization component, at least one kind of ultraviolet absorber monomer having a vinyl group represented by the above formulas (1) to (4) and / or at least one kind of light stabilizer monomer having a vinyl group represented by the following formula (5) are used. The water-soluble resin contained is polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer , Styrene-methacrylic acid copolymer, styrene-acrylic acid-
Acrylic acid alkyl ester copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid alkyl ester copolymer, styrene-maleic Acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl-ethylene copolymer,
Vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, at least one member selected from the group consisting of cyclodextrin and β-cyclodextrin; 6. The recording ink according to any one of the above items. 8. The recording ink according to any one of the above items 1 to 7, wherein the ultraviolet absorber and / or the light stabilizer has an average molecular weight of 3,000 to 50,000. 9. The above 1 wherein the particle size of the water-soluble resin is 150 nm or less
Recording inks of No. 8 to No. 8. Ten. The recording ink according to any one of the above items 1 to 9, wherein the water-soluble resin has an acid value of 7 or less. 11． The above-mentioned 1 to 5, wherein the minimum film-forming temperature of the water-soluble resin is 25 ° C.
10. Recording ink. 12． 12. The recording ink according to claim 1, wherein the water-soluble resin is a pigment dispersant. 13. The recording ink according to any one of the above items 1 to 12, wherein the colorant is a pigment having a particle diameter of 0.01 to 0.15 μm. 14. The recording inks of 1 to 13 above, which contain at least one surfactant selected from the group consisting of surfactants represented by the formulas (I), (II), (III) and (IV). 15． 14. The above 14 containing at least one urea derivative
Recording ink. 16． Wherein the water-soluble organic solvent is a pyrrolidone derivative;
15 recording inks. 17． The recording ink according to any one of the items 1 to 15, which is used for inkjet recording.

[0063]

According to the present invention, in a water-soluble ink containing water and a water-soluble organic solvent as main components, a colorant which disperses or dissolves in water, an ultraviolet absorbent monomer having a vinyl group and / or a light having a vinyl group. By containing a water-soluble resin composed of a stabilizer monomer, high light resistance can be obtained. Furthermore, since sufficient fixability of the colorant to the recording medium can be obtained, a printed body having excellent light resistance, finger touch, abrasion resistance, and water resistance can be obtained. In addition, it is possible to provide an ink jet recording method for plain paper and recycled paper that has high image density and does not cause bleeding, color bleeding, and printing unevenness when using recycled paper.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masato Igarashi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock inside Ricoh Company (72) Inventor Akiko Sakauchi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Inside Ricoh Company (72) Inventor Masayuki Kotani 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (72) Ikuko Yamada 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh F Term (reference) 4J039 AB01 AD01 AD02 AD03 AD08 AD09 AD10 AD11 AD14 AE07 BC09 BC36 BC37 BC50 BE12 BE22 CA03 CA06 EA35 EA36 EA38 EA41 EA42 EA44 EA47 GA24

Claims (16)

[Claims] 1. A colorant which is dispersed or dissolved in water, a UV-absorber monomer having a vinyl group and / or a light stabilizer monomer having a vinyl group, comprising water and a water-soluble organic solvent as main components. A recording ink comprising a water-soluble resin constituted. 2. The method according to claim 1, wherein the water-soluble resin comprises at least one kind of an ultraviolet absorber monomer having at least one vinyl group represented by the following formulas (1) to (4) and / or at least one kind of vinyl group represented by the following formula (5). 2. The recording ink according to claim 1, wherein the recording ink comprises a light stabilizer monomer. Embedded image Embedded image [In each formula, R ₁ = (CH ₂ ) n (n = 1, 2 or 3), and R ₂ represents hydrogen, a methyl group, or a propyl group. ] 3. The ink according to claim 1, wherein the water-soluble resin is contained in the ink in an amount of 0.1 to 20.
The recording ink according to claim 1, wherein the recording ink is contained by weight. 4. The ultraviolet absorbent monomer having a vinyl group is at least one selected from the group consisting of benzotriazoles, benzophenones, cyanoacrylates and salicylic acids. 3. The recording ink according to item 1. 5. A light stabilizer monomer having a vinyl group,
The recording ink according to claim 1, which is a hindered amine-based ink. 6. An ultraviolet absorbent monomer having a vinyl group and / or a light stabilizer monomer having a vinyl group,
1 to 20% by weight of a water-soluble resin.
5. The recording ink according to any one of 5. 7. The ultraviolet absorber and / or the light stabilizer has an average molecular weight of 3,000 to 50,000.
7. The recording ink according to any one of items 1 to 6. 8. The recording ink according to claim 1, wherein the water-soluble resin is a particle having a particle diameter of 150 nm or less. 9. The recording ink according to claim 1, wherein the water-soluble resin has an acid value of 7 or less. 10. The water-soluble resin has a minimum film-forming temperature of 25 ° C.
The recording ink according to claim 1, wherein the recording ink is: 11. The recording ink according to claim 1, wherein the water-soluble resin is a pigment dispersant. 12. The colorant has a particle size of 0.01 to 0.15.
The recording ink according to any one of claims 1 to 11, which is a pigment having a diameter of μm. 13. The compounds of the following formulas (I), (II), (III) and (I)
The recording ink according to any one of claims 1 to 13, further comprising at least one surfactant selected from the group consisting of surfactants represented by V). Embedded image (R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k: 5 to 20). (M and n are 0 to 40) (R is a hydrocarbon chain having 6 to 14 carbon atoms, m, n: 20 or less) 14. The recording ink according to claim 13, comprising at least one urea derivative. 15. The recording ink according to claim 1, wherein the water-soluble organic solvent is a pyrrolidone derivative. 16. The method according to claim 1, which is for ink jet recording.
16. The recording ink according to any one of items 15 to 15.