JP2004131740A - Aqueous printing ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous printing ink giving prints excellent in light-fastness, gasproof and long shelf life, and to provide a method for printing. <P>SOLUTION: The aqueous printing ink comprising at least a colorant and water contains 0.01-2 wt.% benzotriazole compound represented by general formula (I). The benzotriazole compound represented by formula (I) is preferably one or more selected from a group consisting of benzotriazole, benzotriazole sodium salt, 4-methylbenzotriazole, 4-methylbenzotriazole sodium salt and benzotriazole amine salt. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an aqueous recording ink and an ink jet recording method which are excellent in light resistance and gas resistance and can provide a recorded matter which can be stored for a long period of time.

2. Description of the Related Art In recent years, the revolutionary progress of ink jet recording technology has resulted in higher quality images output to a recording medium by ink jet recording, and it has become possible to output high-quality images comparable to silver halide photographs. However, the dye is a colorant which is used in the output of high-quality images, ultraviolet light, light or ozone such as visible light, NO _X, SO _X, easily deteriorated by gas such as H ₂ S, i.e., lightfastness And the gas resistance is poor.
For this reason, the recorded matter inkjet-recorded using the ink containing the dye (dye ink) is inferior in light fastness and gas fastness, and is not only in an environment where strong light is applied, but also in a room or the like. Even in an environment where strong light hardly shines, there is a problem that a recorded image undergoes discoloration over time, that is, the storage stability is poor, and this point is still inferior to silver halide photography.

On the other hand, recording media for inkjet recording mainly include a so-called “swelling type” having an ink receiving layer containing a polymer such as polyvinyl alcohol as a main component, and a fine porous pigment such as amorphous silica and a binder. There is a so-called “void type” (also referred to as an absorption type) having an ink receiving layer contained as a component, but a void type recording medium is superior in terms of ink absorption (quick drying), and therefore, In particular, this gap type recording medium is often used for outputting a high-quality image in which the amount of ejected ink is large. However, since the dye is buried in the polymer, the dyed product is discolored by air oxidation, and the photodegradation of the dye mediated by air is caused in the recorded matter obtained by ink jet recording using the dye ink on the swelling type recording medium. (Determination of singlet oxygen by light and decomposition of dye by singlet oxygen) hardly causes discoloration and discoloration due to deterioration of the dye mediated by air. Since the ink-receiving layer has an infinite number of voids and has high contact with the outside air, the ink-jet-recorded matter using the ink-jet recording is liable to cause deterioration of the dye mediated by air and to be easily discolored. Thus, the deterioration of the dye mediated by air is a problem peculiar to the void type recording medium.

As a method for improving the preservability (in-room preservability) of the recorded matter, a method of incorporating a benzotriazole-based ultraviolet absorber into ink or a recording medium is known.
However, the benzotriazole-based ultraviolet absorber needs to be added in a large amount in order to exhibit its effect, and when the benzotriazole-based ultraviolet absorber is contained in a recording medium, the recording medium base becomes yellowish. Was not practical.

In addition, a problem peculiar to a recording medium having an ink receiving layer containing gelatin as a main component (swelling type recording medium) is that when left open for a long period of time, the image tends to be spotty and the resolution of the image is reduced. (See paragraph No. [0006] in the same publication), a technique has been disclosed in which the ink receiving layer contains a benzotriazole-based compound different from the benzotriazole-based ultraviolet absorber. I have. However, there is still a technique for preventing `` air-mediated deterioration of the dye '' which is a problem peculiar to the gap type recording medium, and improving the preservability of a recorded matter obtained by using the gap type recording medium. Not provided (for example, see Patent Document 1).

JP-A-9-1922

Accordingly, an object of the present invention is to provide a recording material which is excellent in light resistance and gas resistance and which can prevent deterioration of a dye mediated by air peculiar to a gap type recording medium, particularly, discoloration of a recorded image during indoor storage. An object of the present invention is to provide a recording medium and a water-based recording ink which can provide a recorded matter which hardly occurs and can be stored for a long period of time.

The present inventors have conducted various studies on a recording material in which characters and / or images have been formed with a dye ink on a void-type recording medium. As a result, the ink receiving layer and / or the dye ink have a benzotriazole having a specific structure. It has been found that by containing a system compound, deterioration of a dye mediated by air, which is peculiar to a void-type recording medium, can be prevented, and the storage stability (light fastness and gas fastness) of a recorded matter can be improved. did. Further, it has been found that in an ink jet recording method using a benzotriazole-based compound having such a specific structure, a recorded matter having more excellent light resistance can be obtained by further using a specific magenta dye as a coloring material.

The present invention has been made on the basis of the above-described findings, and contains at least 0.01 to 2% by weight of a benzotriazole-based compound represented by the following general formula (I) in an aqueous recording ink containing a coloring material and water. And a water-based recording ink.

Further, the present invention provides an ink jet recording method for forming a character and / or an image on the recording medium with an ink containing a dye represented by the following general formula (II), or ejecting a droplet of the aqueous recording ink. It is another object of the present invention to provide an ink jet recording method for performing printing by attaching the liquid droplets to a recording medium.

According to the aqueous recording ink and the ink jet recording method of the present invention, a recorded matter having excellent light fastness and gas fastness, in particular, hardly causes discoloration of a recorded image during indoor storage, and a recorded matter that can be stored for a long period of time. Can be provided. Further, the aqueous recording ink of the present invention is particularly suitably used for an ink jet recording method. Further, since the recording medium used in the present invention has excellent ink absorbability, it is most suitable for outputting a high-quality image in which the amount of ejected ink is large.

(1) First, the recording medium used in the present invention will be described in detail.

The recording medium of the present invention is a so-called “void-type” recording medium in which the ink receiving layer contains a porous pigment and a binder. The ink receiving layer further includes a benzol represented by the general formula (I). Contains a triazole compound.

In the general formula (I), R represents a hydrogen atom or an alkyl group, and examples of the alkyl group include a substituted or unsubstituted methyl group and a substituted or unsubstituted ethyl group. R is particularly preferably a hydrogen atom.

に お い て In the general formula (I), X represents a hydrogen atom, sodium, potassium or an amine. The amine may be any of primary, secondary, and tertiary. Specifically, for example, the primary amine includes methylamine, ethylamine, propylamine, and the like. The secondary amine includes dimethylamine, Examples include diethylamine and N-methylethylamine. Examples of the tertiary amine include trimethylamine, triethylamine, N, N-dimethylethylamine, and N, N-diethylmethylamine. X is particularly preferably a hydrogen atom.

Preferred specific examples of the benzotriazole-based compound represented by the general formula (I) include, for example, benzotriazole, benzotriazole sodium salt, 4-methylbenzotriazole, 4-methylbenzotriazole sodium salt and benzotriazoleamine salt. One or more selected from the group consisting of: Among these, it is particularly preferable to use benzotriazole from the viewpoint of solubility.

The benzotriazole-based compound represented by the general formula (I) is preferably contained in the ink receiving layer in an amount of 0.01 to 5% by weight, more preferably 0.1 to 3% by weight. . When the content is less than 0.01% by weight, there is no effect on light resistance and gas resistance, and there is a possibility that deterioration of the coloring material due to air cannot be sufficiently prevented. If the content is more than 5% by weight, the ink absorbency may be reduced.

Examples of the porous pigment contained in the ink receiving layer include, for example, a precipitation method, a gel type, a silica-based method such as a gas phase method, smectite clay, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, kaolin, Examples include clay, talc, magnesium silicate, calcium silicate, and the like, and one or more of these are used. Among them, it is particularly preferable to use silica pigments in terms of high purity, price and availability, and among these silica pigments, precipitation method or gel type silica is particularly preferred.

The specific surface area of the porous pigment by BET is determined from the viewpoint of balance between image quality such as color development and resolution of characters and / or images formed on the ink receiving layer and storability. , preferably 100 to 500 m ² / g, more preferably 200 to 400 m ² / g. If the specific surface area by BET is less than 100 m ² / g, the image density may decrease. If the specific surface area exceeds 500 m ² / g, deterioration of the coloring material mediated by air cannot be sufficiently prevented, and the storage quality of the recorded matter is poor. There is a risk.

The average particle size of the porous pigment may be any range as long as it can be used as a normal pigment, but is preferably 0.05 to 15 μm from the viewpoint of improving image quality such as smoothness and resolution of the ink receiving layer. And more preferably 0.1 to 10 μm.

含有 The content of the porous pigment in the ink receiving layer is preferably 40 to 90% by weight, and more preferably 50 to 80% by weight. If the content is less than 40% by weight, the ink absorbency may decrease, and if it exceeds 90% by weight, the coating strength of the ink receiving layer may decrease.

As the binder contained in the ink receiving layer, any binder may be used as long as it has a binding ability and can increase the strength of the ink receiving layer, for example, polyvinyl alcohol, silanol-modified polyvinyl alcohol, vinyl acetate, starch, Cellulose derivatives such as carboxymethyl cellulose, casein, gelatin, conjugated diene-based copolymer latex such as styrene-butadiene copolymer, vinyl-based copolymer latex such as ethylene-vinyl acetate copolymer, and the weight of acrylic acid and methacrylic acid. Acrylic copolymer latex such as coalesced is exemplified, and one or more of these are used. In particular, it is preferable to use polyvinyl alcohol.

含有 The content of the binder is preferably 5 to 60% by weight, more preferably 10 to 50% by weight of the total amount of the porous pigment. If the content is less than 5% by weight, the strength of the ink receiving layer may be reduced. If the content is more than 60% by weight, the absorbability of the ink or the adsorptivity of the coloring material may be reduced.

The ink receiving layer in the recording medium of the present invention may contain a dye fixing agent, a fluorescent whitening agent, a water-proofing agent, a fungicide, a preservative, a dispersant, a surfactant, a thickener, and a pH adjusting agent, if necessary. An additive such as an agent, an antifoaming agent, and a water retention agent can be contained, and one or more of these can be used.

前 記 Examples of the dye fixing agent that can be contained in the ink receiving layer include a cationic organic substance, a polyvalent metal ion, and a cationic surfactant.

Examples of the cationic organic substance include low-molecular weight compounds such as primary to tertiary amine compounds, primary to tertiary amine salts, and quaternary ammonium salts, and primary to tertiary amino groups and primary to tertiary amines. Oligomer having a base or a quaternary ammonium base or a polymer having these groups, and the like, specifically, diallyldimethylammonium chloride polymer, epihalohydrin-secondary amine copolymer, diallyldimethylammonium chloride-sulfur dioxide copolymer, diallyldimethyl Ammonium chloride-acrylamide copolymer, diallylmethyl ammonium salt polymer, diallylamine hydrochloride-sulfur dioxide copolymer, dimethylmethylamine hydrochloride copolymer, polyallylamine, polyethyleneimine, polyethyleneimine quaternary ammonium Arm salt compounds, (meth) acrylamide alkyl ammonium salt polymers, ionene like including a quaternary ammonium base. Examples of the polyvalent metal ion include Al ³⁺ , Ca ²⁺ , and Mg ²⁺ . Examples of the cationic surfactant include benzalkonium chloride. One or more of these are used, and it is particularly preferable to use a polymer having a quaternary ammonium base.

含有 The content of the dye fixing agent is preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, in the ink receiving layer. If the content is less than 0.5% by weight, there is no effect on the improvement of the coloring property and water resistance of the recorded matter. May occur.

Examples of the substrate on which the ink receiving layer is provided include photographic substrates such as paper (including size-treated paper), resin-coated paper obtained by coating polyethylene, polypropylene, and polyester on paper, baryta paper, and RC paper; Examples thereof include thermoplastic resin films such as polyethylene terephthalate, polyethylene, and polypropylene, synthetic paper, and sheets made of synthetic fibers.

The basis weight of the base material is preferably 50 to 120 / m ^2, and still more preferably from 70 to 100 / m ^2.

The thickness of the substrate is preferably from 100 to 240 µm, more preferably from 140 to 200 µm.

記録 The recording medium of the present invention is manufactured, for example, as follows.

First, an aqueous coating solution containing the above-described components (the benzotriazole-based compound represented by the general formula (I), a porous pigment, a binder, a dye fixing agent, and other various additives) is prepared. Then, the aqueous coating solution is coated on the surface of the base material by a known method, for example, a roll coater method, a blade coater method, an air knife coater method, a gate roll coater method, a size press method, and the like. And drying using known drying means such as a far-infrared dryer. Further, from the viewpoint of improving the surface strength and smoothness of the ink receiving layer, calendering or the like may be performed to such an extent that the ink absorbing ability is not reduced.

In the recording medium of the present invention thus manufactured, the coating amount of the ink receiving layer is preferably 10 to 40 g / m ² , and more preferably ²⁰ to 30 g / m ² in terms of solid content. More preferred. When the coating amount is less than 10 g / m ² , there is no effect in terms of the coloring property of the dye as compared with the case where the ink receiving layer is not provided, and when it exceeds 40 g / m ² , powder dropping of the ink receiving layer occurs. There is a risk. The thickness of the ink receiving layer itself is preferably from 10 to 40 μm, more preferably from 20 to 30 μm.

The ink receiving layer preferably has a porosity of 30 to 80%, more preferably 40 to 70%. If the porosity is less than 30%, the quick drying property, absorption speed, absorption capacity, etc. of the ink may be reduced. If the porosity is more than 80%, the porous pigment may fall off, causing slip in the paper feed roll and clogging of the head. May cause. Examples of a method for setting the porosity of the ink receiving layer within the above range include the above-described calender treatment.

空 The porosity of the ink receiving layer is described in J. TAPPI No. It is measured according to 48-85.

As the ink used for recording characters and / or images on the recording medium of the present invention, inks used for recording methods such as an ink jet recording method can be used without particular limitation, and such inks are usually used. , A water-based recording ink containing a coloring material such as a dye or a pigment and water. In the recording medium of the present invention, on which a character and / or an image is formed using the aqueous recording ink, air is interposed by the action of the benzotriazole-based compound represented by the general formula (I). Since deterioration of the coloring material is prevented, the light resistance and the gas resistance are excellent, and the stored image hardly undergoes discoloration and fading especially during indoor storage, and can be stored for a long period of time. In particular, a recorded matter on which a character and / or an image is formed by using an ink containing the dye represented by the general formula (II) (described later) on the recording medium of the present invention is particularly excellent in light resistance. . Further, since the recording medium of the present invention is a so-called void type recording medium, it has excellent ink absorbency (quick drying property) and can sufficiently cope with a large amount of ink ejection.

Next, the water-based recording ink of the present invention will be described in detail.

The aqueous recording ink of the present invention comprises at least 0.01 to 2% by weight, preferably 0.1% by weight of the benzotriazole-based compound represented by the general formula (I) in an aqueous recording ink containing at least a coloring material and water. -1% by weight. When the content is less than 0.01% by weight, there is no effect on light resistance and gas resistance. When the content is more than 2% by weight, flying characteristics of ink droplets may be changed or nozzles may be clogged.

色 The coloring material contained in the aqueous recording ink of the present invention includes a dye and a pigment, and it is preferable to use a dye from the viewpoint of high color density per unit weight and vivid color. As the dye, a water-soluble dye is preferable.Specifically, those which are classified into an acid dye, a direct dye, a mordant dye, a reactive dye, a soluble vat dye, a sulfur dye and an edible dye in a color index are exemplified. Can be

The effect of the present invention of "providing a recorded matter excellent in gas fastness and light fastness" is particularly exhibited when a dye having essentially poor light fastness and gas fastness is used.

The aqueous recording ink of the present invention can provide a recorded matter having excellent light resistance and gas resistance by the action of the benzotriazole-based compound represented by the general formula (I). When the dye represented by the general formula (II) is used, it is possible to provide a recorded material having more excellent light resistance. The dye represented by the general formula (II) is a dye for magenta ink (magenta dye).

好 ま し い Preferred examples of the dye represented by the general formula (II) include, for example, the following dyes M-1 to M-10, and one or more of these dyes can be used.

As the water (main solvent) contained in the aqueous recording ink of the present invention, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water can be used. In particular, it is preferable to use water that has been sterilized by ultraviolet irradiation or addition of hydrogen peroxide in order to prevent the generation of mold and bacteria and to enable long-term storage of the ink.

In the aqueous recording ink of the present invention, if necessary, a penetration enhancer, a surfactant, a wetting agent, a nozzle clogging inhibitor, a preservative / antifungal agent, a pH adjuster, a dissolution aid, an antioxidant, A surface tension adjuster, a viscosity adjuster, a dielectric constant adjuster, an oxygen absorber and the like can be contained, and one or more of these are used.

記録 As a recording medium on which characters and / or images are formed by the aqueous recording ink of the present invention, a recording medium in which the ink receiving layer contains a porous pigment and a binder, that is, a so-called “void type” recording medium is preferable. A recorded matter in which characters and / or images are formed on a void-type recording medium using the aqueous recording ink of the present invention has excellent light resistance and gas resistance, and can be stored for a long period of time.

The recording medium and the aqueous recording ink of the present invention are mainly used as recording paper or recording liquid in an ink jet recording method. The ink jet recording method may be any method as long as it is a method of discharging ink droplets and attaching the liquid droplets to a recording medium to perform printing, but an on-demand type ink jet recording method is particularly preferable. As an on-demand type ink jet recording method, for example, a piezoelectric element recording method of performing recording using a piezoelectric element disposed in a printer head, using thermal energy by a heater of a heating resistor element disposed in the printer head, or the like. The recording medium and the aqueous recording ink of the present invention exhibit excellent effects when recording is performed using any recording method.

Various changes can be made to the present invention without departing from the spirit thereof.

For example, the ink receiving layer in the recording medium of the present invention may be provided on one side of the base material, or may be provided on both sides.

Further, the production of the recording medium of the present invention is performed by a water-based coating method containing components (porous pigment, binder, dye fixing agent and other various additives) other than the benzotriazole-based compound represented by the general formula (I). A method of preparing a liquid, applying the aqueous coating liquid to a substrate, drying the substrate, and immersing the substrate in an aqueous solution containing the benzotriazole-based compound represented by the general formula (I); Alternatively, the method can be carried out by applying the aqueous solution to the substrate by a size press method or spraying it with a spray or the like.

Further, the aqueous recording ink of the present invention contains the benzotriazole-based compound represented by the general formula (I) in the predetermined amount and, if necessary, is represented by the general formula (II) as a coloring material. The composition is similar to that of this type of ink except that a dye is used, and other components that can be contained in the ink are not particularly limited.

〔Example〕
Hereinafter, examples of the present invention will be described. Examples 1, 2, and 6 are examples of the recording medium of the present invention, and Examples 3 to 5 are examples of the aqueous recording ink of the present invention. Comparative Examples 1 to 4 are comparative examples of the recording medium and the aqueous recording ink. However, it goes without saying that the present invention is not limited to such an embodiment.

[Examples 1 and 6]
A coating liquid having the following composition was prepared. The obtained coating liquid was applied to a substrate (trade name “Lumirror 125T”, manufactured by Toray Industries, Inc.) using an air knife coater so that the coating amount after drying was 20 g / m ² . This was dried using a hot air drier (140 ° C., 3 minutes) to provide an ink receiving layer, thereby producing a recording medium 1.

<Composition of coating liquid>
・ Silica 100 parts by weight (trade name “FINE SEAL X37B”, manufactured by Tokuyama Corporation)
・ 400 parts by weight of polyvinyl alcohol (10% aqueous solution) (trade name “Gosenal T-330”, manufactured by Nippon Synthetic Chemical Co., Ltd.)
・ 25 parts by weight of cationic polymer (trade name “Neofix RP-70”, manufactured by Nichika Chemical Co., Ltd.)
・ Benzotriazole 3 parts by weight ・ Water 600 parts by weight

[Example 2]
A recording medium 2 was manufactured in the same manner as in Example 1 except that 3 parts by weight of 4-methylbenzotriazole was used instead of 3 parts by weight of benzotriazole in the coating liquid of Example 1.

[Example 3]
A three-color aqueous recording ink having the following composition was prepared, and an ink set 1 including the three-color aqueous recording inks of cyan (C), magenta (M), and yellow (Y) was manufactured.
The aqueous recording ink was prepared by mixing and dissolving the respective components, and performing pressure filtration with a membrane filter having a pore size of 1 μm.

<Cyan ink composition>
・ C. I. Direct Blue 199 3 parts by weight-Benzotriazole 1 part by weight-Triethylene glycol monobutyl ether 10 parts by weight-Diethylene glycol 10 parts by weight-Glycerin 10 parts by weight-Triethanolamine 1 part by weight-Disodium ethylenediaminetetraacetate 0.01 part by weight- Olfin E1010 1 part by weight ・ Proxel XL-2 0.3 part by weight ・ Ion exchange water 65 parts by weight

<Magenta ink composition>
・ C. I. Acid Red 52 1.5 parts by weight C.I. I. Acid Red 249 1.5 parts by weight-Benzotriazole 1 part by weight-Triethylene glycol monobutyl ether 10 parts by weight-Diethylene glycol 10 parts by weight-Glycerin 10 parts by weight-Triethanolamine 1 part by weight-Disodium ethylenediaminetetraacetate 0.01 part by weight Parts-1 part by weight of Olphin E1010-0.3 parts by weight of Proxel XL-2-65 parts by weight of ion-exchanged water

<Composition of yellow ink>
・ C. I. Acid Yellow 32 2 parts by weight-Benzotriazole 1 part by weight-Triethylene glycol monobutyl ether 10 parts by weight-Diethylene glycol 10 parts by weight-Glycerin 10 parts by weight-Triethanolamine 1 part by weight-Disodium ethylenediaminetetraacetate 0.01 part by weight- Olfin E1010 1 part by weight ・ Proxel XL-2 0.3 part by weight ・ Ion exchange water 65 parts by weight

[Example 4]
A three-color aqueous recording ink having the same composition as the ink set 1 except that 4-methylbenzotriazole was used instead of benzotriazole (the same concentration as benzotriazole) in each ink in the ink set 1 of Example 3 Ink set 2 was manufactured.

[Example 5]
An ink set 3 was prepared having three color aqueous recording inks of the same composition as the ink set 1 except that magenta ink 2 of the following composition was used instead of magenta ink in ink set 1 of Example 3.

<Composition of magenta ink 2>
-4 parts by weight of the dye M-1-1 part by weight of benzotriazole-10 parts by weight of triethylene glycol monobutyl ether-10 parts by weight of diethylene glycol-10 parts by weight of glycerin-1 part by weight of triethanolamine-disodium ethylenediaminetetraacetate 0.01 Parts by weight-Orfin E1010 1 part by weight-Proxel XL-2 0.3 part by weight-Deionized water 65 parts by weight

[Comparative Example 1]
A recording medium 3 was manufactured in the same manner as in Example 1 except that benzotriazole was not used in the coating liquid of Example 1.

イ ン ク In addition, an ink set 4 was prepared which had the same composition as the ink set 1 except that no benzotriazole was contained in each ink in the ink set 1 of Example 3 except that benzotriazole was not contained.

[Comparative Example 2]
In the ink set 3 of the fifth embodiment, an ink set 5 including three color aqueous recording inks having the same composition as the ink set 3 except that benzotriazole was not contained in each ink was manufactured.

[Comparative Example 3]
A recording medium 4 was manufactured in the same manner as in Example 1 except that a coating liquid having the following composition was used instead of the coating liquid of Example 1.

<Composition of coating liquid>
・ Silica 100 parts by weight (trade name “FINE SEAL X37B”, manufactured by Tokuyama Corporation)
・ 400 parts by weight of polyvinyl alcohol (10% aqueous solution) (trade name “Gosenal T-330”, manufactured by Nippon Synthetic Chemical Co., Ltd.)
・ 25 parts by weight of cationic polymer (trade name “Neofix RP-70”, manufactured by Nichika Chemical Co., Ltd.)
・ 10 parts by weight of benzotriazole-based UV absorber (solid content 30%) (trade name “ADK STAB LX-301”, manufactured by Asahi Denka Kogyo Co., Ltd.)
・ 600 parts by weight of water

[Comparative Example 4]
A recording medium 5 was prepared in the same manner as in Example 1 except that a coating liquid having the following composition was applied instead of the coating liquid of Example 1 so that the coating amount after drying was 10 g / m ^2. Manufactured.

<Composition of coating liquid>
・ Lime-treated gelatin 70 parts by weight ・ Polyvinyl pyrrolidone 70 parts by weight (trade name “PVP-90”, manufactured by BASF)
・ 25 parts by weight of cationic polymer (trade name “Neofix RP-70”, manufactured by Nichika Chemical Co., Ltd.)
-Benzotriazole 3 parts by weight-Surfactant 1 part by weight (trade name "Megafax F-120", manufactured by Dainippon Ink and Chemicals, Inc.)
・ Water 1800 parts by weight

[Evaluation of light resistance, indoor storage stability and ozone resistance]
Using an ink jet printer (trade name “MJ-930C”, manufactured by Seiko Epson Corporation) loaded with each of the ink sets 1 to 5, the recording medium 1 was combined with the ink set and the recording medium shown in Table 1 below. On each of Nos. 5 to 5, composite black and single-color solid printing of each color of C, M, and Y were performed to produce recorded matters. The recorded matter was evaluated by the following [Method for evaluating light resistance], [Method for evaluating indoor storage stability] and [Method for evaluating ozone resistance]. The results are shown in Table 1 below. In addition, the printing method was prepared so that the composite black was composed of the aqueous recording inks of three colors of C, M and Y.

[Evaluation method of light resistance]
Using a xenon weatherometer Ci35A (manufactured by Atlas Electric Devices Co., Ltd.) at a temperature of 40 ° C., a relative humidity of 50% RH, a black panel temperature of 63 ° C. and an illuminance of 0.25 W / m ² at 340 nm, Light irradiation treatment (light irradiation time: 50 hours).

The optical density (OD) of each of the C, M, and Y color portions in the recorded matter before and after the light irradiation treatment was measured using a Gretag densitometer (manufactured by Gretag), and the optical density residual ratio (ROD) was calculated by the following equation. I asked.
ROD (%) = (D / D ₀ ) × 100
D: OD of recorded matter after light irradiation treatment
D ₀ : OD of recorded matter before light irradiation treatment
The larger the value of ROD, the better the light resistance.

[Evaluation method for indoor storage stability]
The recorded matter was stuck on a wall in a room (room temperature 24 ° C., relative humidity 60% RH) and left for one month. The color difference (ΔE ^* ab) of the Bk color portion immediately after printing of the recorded matter was determined (based on JIS Z 8730). The smaller the value of ΔE ^* ab, the better the room storage stability.

[Ozone resistance evaluation criteria]
The recorded matter was left for 120 minutes in a light-shielded tank maintained at a temperature of 24 ° C., a relative humidity of 60% RH, and an ozone concentration of 10 ppm for ozone treatment. The color difference (ΔE ^* ab) of the Bk color portion of the recorded matter before ozone treatment was determined (based on JIS Z 8730). The smaller the value of ΔE ^* ab, the better the ozone resistance.

[Evaluation of ink absorbency]
Using the ink jet printer, printing was performed so that the reflection densities of cyan, magenta, and yellow would be 2.0 or more, respectively, using a combination of the ink set and the recording medium shown in Table 1 below. The paper was overlaid on the printing section and lightly pressed. The degree of the amount of ink transferred to the PPC paper was visually observed and evaluated according to the following evaluation criteria.
<Evaluation criteria>
：: No transfer at all.
Δ: Transfer slightly.
×: Transfer considerably.

As is clear from the results shown in Table 1, recorded matter obtained using the recording medium 1 or 2 containing the benzotriazole-based compound represented by the general formula (I) (Examples 1, 2, and 6) And the recorded matter (Examples 3 to 5) obtained using any one of the ink sets 1 to 3 provided with the aqueous recording ink containing the benzotriazole-based compound, Compared to the recorded matter (Comparative Examples 1 to 4) obtained using the media 3 to 5 and the ink set 4 or 5 provided with the aqueous recording ink not containing the benzotriazole-based compound, the light resistance and the room It turns out that it is excellent in storage stability and ozone resistance. The recorded matter of Comparative Example 3 was obtained by using the recording medium 4 containing a normal benzotriazole-based ultraviolet absorber, but was inferior in each of the above-described characteristics as compared with each recorded matter of the Example. Thus, the effectiveness of the benzotriazole-based compound represented by the general formula (I) according to the present invention is clear.
In the first place, the recording medium 4 had a slightly yellowish surface on the ink receiving layer and could not be used practically.

Further, solid printing of magenta in the recorded matter of Examples 5 and 6 obtained using the ink set 3 or 5 provided with the magenta ink containing the dye (M-1) represented by the general formula (II) It can be seen that the portion has better light fastness than the solid printed portion of magenta in other recorded materials.

Further, since the recorded matter of Comparative Example 4 was obtained by using the so-called swelling type recording medium 5, the ink absorbing property was higher than that of the void-type recorded matter of Example and other comparative examples. The result was inferior.

Claims (7)

An aqueous recording ink containing at least 0.01 to 2% by weight of a benzotriazole compound represented by the following general formula (I) in an aqueous recording ink containing at least a coloring material and water.

The benzotriazole-based compound represented by the general formula (I) is one selected from the group consisting of benzotriazole, benzotriazole sodium salt, 4-methylbenzotriazole, 4-methylbenzotriazole sodium salt, and benzotriazoleamine salt 2. The aqueous recording ink according to claim 1, which is a combination of two or more types. (3) The aqueous recording ink according to (1) or (2), wherein the coloring material is a dye. The aqueous recording ink according to claim 3, wherein the dye is a dye represented by the following general formula (II).

The aqueous recording ink according to any one of claims 1 to 4, which is used in an inkjet recording method. The aqueous recording ink according to any one of claims 1 to 5, wherein the ink receiving layer is used when forming characters and / or images on a recording medium containing a porous pigment and a binder. An ink jet recording method for discharging a droplet of the aqueous recording ink according to any one of claims 1 to 6, and adhering the droplet to a recording medium to perform printing.