JP2006182944A - Ink composition, ink-jet recording method using the same and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition excellent in solidity (mainly in light resistance) of printed matter and anti-bronze resistance, an ink-jet recording method using the same, and recorded matter recorded by the recording method. <P>SOLUTION: This ink composition comprises at least water, C.I. direct yellow 98, an aromatic compound having a carboxylic group, and/or its salt. This ink-jet recording method uses this ink, and this recorded matter is recorded by the recording method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an ink composition suitable for ink jet recording, in particular, an ink composition excellent in fastness to printed matter (mainly light resistance) and bronze resistance, an ink jet recording method using the ink composition, and recording by the recording method Concerning recorded materials.

  Inkjet recording is a method of recording characters and images (hereinafter sometimes simply referred to as “images”) on the surface of a recording medium by ejecting ink compositions as small droplets from fine nozzles. As an ink jet recording method, an electric signal is converted into a mechanical signal using an electrostrictive element, and an ink composition stored in a nozzle head portion is intermittently ejected to record characters and images on the surface of the recording medium. The ink composition stored in the nozzle head part is rapidly heated at a part close to the ejection part to generate bubbles, and ejected intermittently by volume expansion due to the bubbles, and characters and images are printed on the surface of the recording medium. A recording method has been put to practical use.

  In addition, as an ink composition for inkjet recording, in general, various dyes are dissolved in water or an organic solvent, or a mixed solution thereof from the viewpoint of safety and printing characteristics. More strict conditions are required as compared to ink compositions for writing instruments such as fountain pens and ballpoint pens.

In particular, in recent years, inkjet printers have come to be used for the production of printed materials for advertisement, and when forming a color image using a plurality of ink compositions, it is much more. Strict demands are being made.
This is because, in a color image formed by a plurality of ink compositions, if there is one color that is inferior in hue, the color balance of the entire image is inferior because of the hue, and a high-quality image cannot be obtained. Because it will be.
In general, metal complex dyes are excellent in light fastness and are expected to be used in the above applications. On the other hand, metal is printed on a portion printed at a high duty such as solid printing (100% duty fill printing). A phenomenon that causes gloss (hereinafter referred to as “bronze phenomenon”) is likely to occur. In such a case, the color balance of the entire image becomes non-uniform and the image quality is deteriorated. Therefore, the improvement is desired.
In recent years, glossy paper has been widely used as a recording medium with a texture close to that of a photographic tone, but due to the bronze phenomenon of specific colors, the glossiness on the surface of the printed matter varies, and the image Therefore, the improvement is strongly desired from the viewpoint of maintaining the glossiness of the entire image.

  In addition, the printed matter created using the ink composition as described above may be installed not only indoors but also outdoors, so that it is exposed to various kinds of light such as sunlight. In particular, yellow ink compositions with improved light resistance are conspicuous from the standpoint of the dye itself, and the bronze phenomenon is conspicuous and improvement is desired.

In addition, it is known that a so-called bronzing phenomenon occurs when printing is performed on a recording medium having a high acidity when, for example, a dye having poor water solubility is used in an ink composition for ink jet recording.
As countermeasures, it is common practice to add alcohol amines as pH maintainers or to increase the penetrating power into paper. Basically, the bronze phenomenon is caused by crystallization of the dye due to drying of the ink composition on the paper surface, and the above method prevents crystallization by increasing this solubility, or prevents the crystallization in the paper before crystallization. It is effective from the viewpoint of making it penetrate. However, in the former, the pH easily rises to around 11 due to the addition, causing concern about corrosion of the nozzles of the printer and the influence on the human body. Other print quality deterioration such as bleed phenomenon is caused and is not a perfect solution.
In order to solve this problem, an ink composition to which 2-oxo-oxazolidone or 1,3-bis (βhydroxyethyl) urea is added has been proposed as an alternative measure (see, for example, Patent Document 1). .
In addition, an ink composition has been proposed that solves this problem by adding a basic amino acid (see, for example, Patent Document 2).
However, unfortunately, from the results of various investigations and researches by the present inventors, C.I. which is excellent in printed fastness (mainly light resistance) even when the measures described above are used. I. It has been found that the ink composition using Direct Yellow 98 has no effect on eliminating / releasing the bronze phenomenon.

JP-A-6-25575 JP 7-228810 A

  Accordingly, the present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide an ink composition excellent in printed matter fastness (mainly light resistance), bronze To provide an ink composition that is further excellent in terms of improvement of phenomena, and further to provide an ink composition that is also improved in terms of clogging resistance, an ink jet recording method using them, and recording by the recording method To provide a record.

  We have described C.I. I. As a result of further investigation and research on the light resistance of Direct Yellow 98, measures to prevent bronzing, etc., C.I. I. When an aromatic compound having a carboxyl group and / or a salt thereof was added to the ink composition containing Direct Yellow 98, it was found that the bronzing phenomenon was improved without impairing the light resistance of the printed matter. The present invention has been completed based on the above.

1. The ink composition according to the present invention includes at least water and C.I. I. It is characterized by comprising Direct Yellow 98 and an aromatic compound having a carboxyl group and / or a salt thereof.

2. The ink composition according to the present invention is the ink composition according to the item 1, wherein the aromatic compound having a carboxyl group and / or a salt thereof is an aromatic compound having one carboxyl group and / or a salt thereof. It is characterized by that.

3. The ink composition according to the present invention is the ink composition according to 1 or 2, wherein the aromatic compound having a carboxyl group and / or a salt thereof is a compound having a naphthalene skeleton and / or a salt thereof. Features.

4). The ink composition according to the present invention is the ink composition according to the above item 3, wherein the compound having a naphthalene skeleton and / or a salt thereof includes a carboxyl group in the naphthalene skeleton and an -OR group (R: C1-C6 alkyl). And / or a salt thereof.

5. The ink composition according to the present invention is the ink composition described in 4 above, wherein the compound having a naphthalene skeleton and / or a salt thereof has one carboxyl group in the naphthalene skeleton, and an -OR group (R: C1-C6). A compound having one alkyl group and / or a salt thereof.

6). The ink composition according to the present invention is the ink composition according to any one of 3 to 5, wherein the compound having a naphthalene skeleton and / or a salt thereof has a carboxyl group at the 2-position and / or a salt thereof. It is characterized by being.

7). The ink composition according to the present invention is the ink composition according to 6, wherein the compound having a carboxyl group at the 2-position and having a naphthalene skeleton and / or a salt thereof is 1-hydroxy-2-naphthoic acid, 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, 3-methoxy-2-naphthoic acid, 6-methoxy-2-naphthoic acid, 6-ethoxy-2-naphthoic acid, It is characterized by being at least one of 6-propoxy-2-naphthoic acid and salts thereof.

8). The ink composition according to the present invention is the ink composition according to any one of 1 to 7, wherein the aromatic compound having a carboxyl group and / or a salt thereof is added in an amount of 0.1 to 10 with respect to the total amount of the ink composition. It is characterized by comprising% by weight.

9. The ink composition according to the present invention is the ink composition according to any one of 1 to 8, wherein the C.I. I. The content ratio of the direct yellow 98 and the aromatic compound having a carboxyl group and / or a salt thereof is in the range of 1: 0.5 to 1:10.

10. The ink composition according to the present invention is characterized in that in the ink composition described in any one of 1 to 9 above, the ink composition further comprises a nonionic surfactant.

11. The ink composition according to the present invention is characterized in that the nonionic surfactant described in 10 is an acetylene glycol surfactant.

12 The ink composition according to the present invention is characterized in that, in the ink composition as described in 10 or 11 above, 0.1 to 5% by weight of a nonionic surfactant is contained with respect to the total amount of the ink composition.

13. The ink composition according to the present invention is the ink composition according to any one of 1 to 12, further comprising a penetration enhancer.

14 The ink composition according to the present invention is characterized in that the penetration enhancer described in 13 is a glycol ether.

15. The ink composition according to the present invention is characterized in that in the ink composition described in any one of 1 to 14 above, the pH of the ink composition at 20 ° C. is 8.0 to 10.5.

16. The ink composition according to the present invention is the ink composition according to any one of 1 to 15 used in an inkjet recording method.

17. The ink composition according to the present invention is characterized in that the ink jet recording method described in 16 is a recording method using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element.

18. An ink jet recording method according to the present invention is an ink jet recording method in which a droplet of an ink composition is ejected and the droplet is attached to a recording medium for recording, and the ink composition is any one of the above 1 to 15 The ink composition described in 1) is used.

19. The recorded matter according to the present invention is recorded using the ink composition described in any one of 1 to 17 above or by the recording method described in 18 above.

  The present invention provides at least C.I. I. When the ink composition containing Direct Yellow 98 contains an aromatic compound having a carboxyl group and / or a salt thereof, those recorded using the ink composition are excellent in printed fastness (mainly light resistance). In addition, an excellent effect is obtained that an image free from bronzing can be obtained.

  The ink composition of the present invention contains at least C.I. in an aqueous medium comprising water or water and a water-soluble organic solvent. I. It contains an aromatic compound having direct yellow 98 and a carboxyl group and / or a salt thereof, and may contain a moisturizing agent, a viscosity adjusting agent, a pH adjusting agent and other additives as necessary.

  As the dye species contained in the ink composition of the present invention, at least C.I. I. There is no particular limitation as long as the direct yellow 98 is included, and if necessary, any colorant that can exhibit a yellow color can be included alone or in combination of two or more.

In general, when a solid printing is performed on an ink jet recording medium (particularly a glossy recording medium) using an ink composition containing a metal complex dye, a bronzing phenomenon may be observed. Metal complex dyes generally have a strong cohesive force on paper, and as a result, exhibit high print fastness (especially light resistance) and at the same time tend to increase the bronze phenomenon for the same reason.
C. in the present invention. I. In order to obtain a high-quality inkjet recording material having no bronze phenomenon with respect to an ink composition containing at least Direct Yellow 98, the following aromatic compound having a carboxyl group can be included.

  C. I. The content of the dye containing Direct Yellow 98 is determined by the type of other dye used, the type of solvent component, etc., but is 0.1 to 10% by weight, preferably 0, based on the total weight of the ink composition. The range is from 5 to 5% by weight. By setting the content to 0.1% by weight or more, it is possible to ensure color developability or image density on the recording medium. Such characteristics can be easily secured.

The ink composition of the present invention has C.I. I. In order to reduce or eliminate the bronzing phenomenon observed when solid printing is performed using an ink composition containing Direct Yellow 98, at least an aromatic compound having a carboxyl group or a salt thereof is used. Contains one. When the aromatic compound having a carboxyl group contains an -OR group (R: C1-C6 alkyl group), the effect of improving the bronze phenomenon is remarkably excellent, and the nitrogen oxide resistance is remarkably good. Results are shown.
That is, in the present invention, water and C.I. I. If the ink composition contains Direct Yellow 98 and at least one aromatic compound having a carboxyl group or a salt thereof, not only the yellow ink composition but also, for example, a color different from yellow such as a black ink composition, etc. Even an ink composition can weaken or eliminate the bronzing phenomenon seen when solid printing is performed. In order to produce these various ink compositions, they can be used in combination with other conventionally known dyes.

The aromatic compound having a carboxyl group or a salt thereof used in the present invention may be any aromatic compound or salt thereof having at least one carboxyl group in the molecular structure, but at least one carboxyl group is included. A compound having a naphthalene skeleton or a salt thereof is preferable, a compound having a carboxyl group at the 2-position, and a compound having a naphthalene skeleton or a salt thereof is more preferable, and a compound having a carboxyl group at the 2-position is more preferable. An alkali metal salt of a compound having
Further, a compound or salt having at least one carboxyl group and at least one —OR group (R: C1-C6 alkyl group) in the naphthalene skeleton is more preferable, and among them, the carboxyl group is in the 2-position, and the naphthalene skeleton A compound or salt having the above is not only particularly preferable from the viewpoint of improving bronze resistance, but also preferable from the viewpoint of nitrogen oxide resistance.
Specific examples of the aromatic compound having a carboxyl group or a salt thereof include 1-naphthoic acid, 2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy- 2-naphthoic acid, 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 2,6-naphthalenedicarboxylic acid, 3-methoxy-2-naphthoic acid, 3-ethoxy-2-naphthoic acid, 3-propoxy- Examples include 2-naphthoic acid, 6-methoxy-2-naphthoic acid, 6-ethoxy-2-naphthoic acid, 6-propoxy-2-naphthoic acid, and salts thereof.
The salt of the aromatic compound having a carboxyl group is added in the form of a salt and can be contained in the ink. In addition, the aromatic compound having a carboxyl group and the base are added separately, It is also possible to contain.

  The content of the aromatic compound having a carboxyl group and / or a salt thereof is determined by the kind of the aromatic compound having a carboxyl group and / or a salt thereof, the kind of the dye, the kind of the solvent component, and the like. It is 0.1 to 10% by weight, preferably 0.5 to 5% by weight based on the total weight of the product.

  In the ink composition of the present invention, C.I. I. The content ratio of direct yellow 98 and an aromatic compound having a carboxyl group and / or a salt thereof is preferably in the range of 1: 0.5 to 1:10, more preferably 1: 1 to 1: 6. By increasing the ratio of the aromatic compound having a carboxyl group and / or a salt thereof higher than 1: 0.5, the effect of improving the bronzing phenomenon can be sufficiently obtained, and the carboxyl group can be added more than 1:10. By reducing the ratio of the aromatic compound and / or salt thereof, clogging reliability and the like can be easily ensured.

  In order to stably dissolve the amount of the predetermined dye and the aromatic compound having a carboxyl group and / or a salt thereof, the pH (20 ° C.) of the ink composition is preferably 8.0 or more. In consideration of material resistance with various members in contact with the ink composition, the pH of the ink composition is preferably 10.5 or less. In order to make these matters more compatible, it is more preferable to adjust the pH of the ink composition to 8.5 to 10.0.

The ink composition of the present invention may further contain a humectant selected from water-soluble organic solvents and / or saccharides having a vapor pressure lower than that of pure water.
By including the humectant, the ink can be moisturized by suppressing evaporation of moisture in the ink jet recording system. In addition, if it is a water-soluble organic solvent, the viscosity can be easily changed without improving the ejection stability or changing the ink characteristics.
The water-soluble organic solvent refers to a medium having an ability to dissolve a solute, and is selected from organic and water-soluble solvents having a vapor pressure smaller than that of water. Specifically, ethylene glycol, propylene glycol, butanediol, pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 1,2,6-hexanetriol, diethylene glycol Desirable are polyhydric alcohols such as triethylene glycol and dipropylene glycol, ketones such as acetonyl acetone, esters such as γ-butyrolactone and triethyl phosphate, furfuryl alcohol, tetrahydrofurfuryl alcohol, thiodiglycol and the like. . The saccharide is preferably maltitol, sorbitol, gluconolactone, maltose or the like.
The humectant is preferably added in an amount of 5 to 50% by weight, more preferably 5 to 30% by weight, and still more preferably 5 to 20% by weight with respect to the total amount of the ink composition. If it is 5% by weight or more, moisture retention can be obtained, and if it is 50% by weight or less, it is easy to adjust the viscosity used for inkjet recording.

The ink composition of the present invention preferably contains a nitrogen-containing organic solvent as a solvent. Examples of the nitrogen-containing organic solvent include 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidone, N-methyl-2-pyrrolidone, and ε-caprolactam. Among them, 2-pyrrolidone is preferably used. be able to. They can be used alone or in combination of two or more.
The content is preferably 0.5 to 10% by weight, and more preferably 1 to 5% by weight. By making the content 0.5% by weight or more, it is possible to improve the solubility of the coloring material of the present invention by adding, and by making the content 10% by weight or less, various kinds of ink compositions that come into contact with it. The material resistance with the member is not deteriorated.

  In addition, the ink composition of the present invention contains a nonionic surfactant as an additive effective for obtaining rapid fixing (penetration) of the ink and at the same time maintaining the roundness of one dot. Is preferred.

  Examples of nonionic surfactants used in the present invention include acetylene glycol surfactants. Specific examples of the acetylene glycol surfactant include Surfynol 465, Surfynol 104, Olphine STG (manufactured by Nissin Chemical Industry Co., Ltd., trade name), and the like. The addition amount is 0.1 to 5% by weight, preferably 0.5 to 2% by weight. When the addition amount is 0.1% by weight or more, sufficient penetrability can be obtained, and when the addition amount is 5% by weight or less, it is easy to prevent image blurring.

  Furthermore, by adding glycol ethers as penetration enhancers in addition to nonionic surfactants, the penetration is further increased and the bleed at the boundary with the adjacent color ink is reduced when color printing is performed. And a very clear image can be obtained.

  Examples of glycol ethers used in the present invention include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, Examples include triethylene glycol monobutyl ether. The addition amount is 3 to 30% by weight, preferably 5 to 15% by weight. If the addition amount is less than 3% by weight, the effect of preventing bleeding cannot be obtained. If the amount exceeds 30% by weight, not only the image will bleed, but also oily separation will occur, so the dissolution aid for these glycol ethers will be required, which will increase the viscosity of the ink. Becomes difficult.

  Furthermore, the ink composition of the present invention includes a pH adjuster such as triethanolamine or alkali metal hydroxide, a hydrotrope such as urea and its derivatives, a water-soluble polymer such as sodium alginate, if necessary. A water-soluble resin, a fluorine-based surfactant, a fungicide, a rust inhibitor, and the like may be added.

  As a method for preparing the ink composition of the present invention, for example, each component is sufficiently mixed and dissolved, pressure-filtered through a membrane filter having a pore size of 0.8 μm, and then degassed using a vacuum pump. There is.

  Next, the recording method of the present invention using the above-described ink composition will be described. In the recording method of the present invention, an ink jet recording method in which an ink composition is ejected as droplets from fine holes and the droplets are attached to a recording medium for recording can be used particularly preferably. Needless to say, it can also be used for applications such as pen plotters.

  As the ink jet recording method, any of the conventionally known methods can be used, and in particular, a method of ejecting droplets using vibration of a piezoelectric element (using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element). Recording method) and a method using thermal energy, it is possible to perform excellent image recording.

Next, the present invention will be specifically described with reference to examples and comparative examples of the present invention.
The present invention is not limited to the following examples.

[Examples 1 to 3 and Comparative Example 1]
The ink compositions used in Examples 1 to 3 and Comparative Example 1 were prepared by mixing and dissolving each component at the blending ratio shown in Table 1, and performing pressure filtration with a membrane filter having a pore size of 1 μm. In addition, each component of the ink composition shown in Table 1 indicates weight% of each component with respect to the total amount of the ink composition, and the remaining amount is water.

  The ink composition described in Examples 1 to 3 and Comparative Example 1 is filled into a dedicated cartridge (yellow chamber) using an ink jet printer EM930C (manufactured by Seiko Epson Corporation), and an ink jet exclusive recording medium (PM photographic paper, exclusive glossy film: both manufactured by Seiko Epson Corporation) were printed, and bronze evaluation and light resistance evaluation were performed. The obtained results are shown in Table 2.

《Bronze evaluation》
Using the above cartridge, a printed matter obtained by solid printing so as to give a driving amount of 1.5 to 2.2 mg per inch square meter was visually determined based on the following criteria.
[Evaluation criteria]
Evaluation A: Bronze phenomenon is not seen at all.
Evaluation B: Some bronze phenomenon is observed.
Evaluation C: The bronze phenomenon is conspicuous.

<< Evaluation of light resistance >>
Using the cartridge filled with the ink composition described in Examples 1 to 3 and Comparative Example 1, the applied duty was adjusted so that OD (Optical Density) was in the range of 0.9 to 1.1. The printed matter obtained by printing was exposed for 6 days using Ci-5000 (manufactured by Atlas Electric Device Co., Ltd.). After the exposure, the OD of each printed matter was measured using a densitometer (Spectrolino: manufactured by Gretag), the optical density residual ratio (ROD) was determined by the following formula, and evaluated according to the following criteria.

ROD (%) = (D / D0) × 100
D: OD after exposure test
D0: OD before exposure test
(However, measurement conditions are Filter: Blue, Light source: D50, Viewing angle: 2 degrees) [Criteria]
Evaluation A: ROD is 80% or more Evaluation B: ROD is 70% or more and less than 80% Evaluation C: ROD is less than 70%

  The ink composition of the present invention is excellent in fastness to printed matter and bronze resistance, and can be applied to an ink composition for ink jet recording, a recording method using the ink composition, and an ink jet recording system including a recorded matter recorded by the recording method. It has applicability in a wide range of related fields.

Claims (19)

At least water and C.I. I. An ink composition comprising Direct Yellow 98 and an aromatic compound having a carboxyl group and / or a salt thereof. The ink composition according to claim 1, wherein the aromatic compound having a carboxyl group and / or a salt thereof is an aromatic compound having one carboxyl group and / or a salt thereof. The ink composition according to claim 1, wherein the aromatic compound having a carboxyl group and / or a salt thereof is a compound having a naphthalene skeleton and / or a salt thereof. 4. The compound having a naphthalene skeleton and / or a salt thereof is a compound having a carboxyl group and an -OR group (R: C1-C6 alkyl group) in the naphthalene skeleton and / or a salt thereof. Ink composition. The compound having a naphthalene skeleton and / or a salt thereof is a compound and / or a salt thereof having one carboxyl group and one -OR group (R: C1-C6 alkyl group) in the naphthalene skeleton. Item 5. The ink composition according to Item 4. The ink composition according to any one of claims 3 to 5, wherein the compound having a naphthalene skeleton and / or a salt thereof is a compound having a carboxyl group at the 2-position and / or a salt thereof. The compound having a carboxyl group at the 2-position and having a naphthalene skeleton and / or a salt thereof are 1-hydroxy-2-naphthoic acid, 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2. -Naphthoic acid, 3-methoxy-2-naphthoic acid, 6-methoxy-2-naphthoic acid, 6-ethoxy-2-naphthoic acid, 6-propoxy-2-naphthoic acid and salts thereof, Item 7. The ink composition according to Item 6. The ink composition according to any one of claims 1 to 7, comprising 0.1 to 10% by weight of the aromatic compound having a carboxyl group and / or a salt thereof based on the total amount of the ink composition. C. above. I. The content ratio of the aromatic compound which has direct yellow 98 and the said carboxyl group, and / or its salt is the range of 1: 0.5-1: 10, It is any one of Claims 1-8. Ink composition. Furthermore, the ink composition as described in any one of Claims 1-9 which comprises a nonionic surfactant. The ink composition according to claim 10, wherein the nonionic surfactant is an acetylene glycol surfactant. The ink composition according to claim 10 or 11, comprising 0.1 to 5% by weight of the nonionic surfactant based on the total amount of the ink composition. The ink composition according to any one of claims 1 to 12, further comprising a penetration enhancer. The ink composition according to claim 13, wherein the penetration enhancer is glycol ether. The ink composition according to any one of claims 1 to 14, wherein the pH of the ink composition at 20 ° C is 8.0 to 10.5. The ink composition according to any one of claims 1 to 15, which is used in an inkjet recording method. The ink composition according to claim 16, wherein the ink jet recording method is a recording method using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element. An ink jet recording method for performing recording by ejecting droplets of an ink composition and attaching the droplets to a recording medium, wherein the ink composition according to any one of claims 1 to 15 is used. An ink jet recording method using the method. A recorded matter recorded using the ink composition according to any one of claims 1 to 17, or recorded by the recording method according to claim 18.