JP2011195683A - Ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition excellent in clogging recovering property without impairing fluorescence intensity and color development, and a recording method using this.SOLUTION: The ink composition includes at least C.I. acid red 52 and triethylene glycol. The ink composition in which the ratio of contents of the C.I. acid red 52 and the triethylene glycol is within a specific range is used for the inkjet recording method.

Description

Background of the Invention

The present invention relates to an ink composition comprising a fluorescent dye and an ink jet recording method using the same.

Background Art Red fluorescent ink is used in a fee-based printing machine for imprinting postage charges or indicia of postage-based mail. In particular, in North America, red fluorescent ink that can be read by an automatic reading device used in the US Postal Service is designated as an ink used for indicia of postage-based mail.

  In the automatic reading device, not only the reading of the bar code but also the detection of the front and back of the mail is simultaneously performed. Therefore, the red fluorescent ink requires not only a high optical density for improving barcode reading accuracy but also a high fluorescent intensity for reducing detection errors on the front and back sides of the detected mail.

  JP-A-9-291246 (Patent Document 1) discloses a fluorescent fluorescent ink excellent in water resistance, to which glycol ether is added as an auxiliary solvent penetrating agent, as a fluorescent ink for postage by postage.

  Japanese Patent Laid-Open No. 2006-131667 (Patent Document 2) discloses C.I. I. A water-soluble fluorescent colorant using Acid Red 52 and 92 and C.I. I. Disclosed is a water-based fluorescent ink having a good fluorescence coloring property using a pigment dispersion solution composed of CI Pigment Red 122 or the like.

  However, although the fluorescent dye is weak in light resistance, when another dye or the like is mixed in order to improve the light resistance, the fluorescence intensity may suddenly decrease due to the interaction between the fluorescent dye and another dye.

  In addition, C.I. I. To the red fluorescent ink composition using Acid Red 52 and 92, C.I. I. By using Direct Yellow 87 in combination, a red fluorescent ink composition excellent in fluorescence intensity and color developability (optical density) has been provided (JP 2009-256544 A: Patent Document 3). In addition, it can be said that an ink composition excellent in clogging recovery without impairing color development (optical density) is still desired.

JP-A-9-291246 JP 2006-131667 A JP 2009-256544 A

  The present inventors have now described C.I. I. An ink composition comprising at least Acid Red 52 and triethylene glycol, wherein the C.I. I. By using an ink composition in which the content ratio of Acid Red 52 and the triethylene glycol is within a specific range, the ink composition is excellent in clogging recovery without impairing the fluorescence intensity and color developability. The knowledge that a thing is obtained was acquired. The present invention is based on these findings.

  Accordingly, an object of the present invention is to provide an ink composition excellent in clogging recovery without impairing the fluorescence intensity and the color developability.

The ink composition according to the present invention includes C.I. I. An ink composition comprising at least Acid Red 52 and triethylene glycol,
C. above. I. In the ink composition, the content ratio of Acid Red 52 to the triethylene glycol is 1: 5 to 1:23.

  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 to perform printing, and uses the ink composition.

  According to the present invention, it is possible to provide an ink composition excellent in clogging recovery without impairing fluorescence intensity and color developability.

Detailed description of the invention

Ink composition The ink composition according to the present invention comprises C.I. I. An ink composition comprising at least Acid Red 52 and triethylene glycol, wherein C.I. I. Since the content ratio of Acid Red 52 and triethylene glycol is 1: 5 to 1:23, an ink composition excellent in clogging recovery performance is obtained without impairing fluorescence intensity and color developability. Obtainable. Hereinafter, each component contained in the ink composition of the present invention will be described.

<Dye>
The ink composition according to the present invention includes C.I. I. At least Acid Red 52 is included.

  In the present invention, the C.I. I. The acid red 52 is preferably contained in an amount of 0.05 to 0.2% by mass, and more preferably 0.08 to 0.1% by mass with respect to the ink composition. By setting it within this range, an ink composition excellent in clogging recovery can be obtained without impairing the fluorescence intensity and the color developability.

  The ink composition according to the present invention is not particularly limited as long as an ink composition excellent in clogging recovery property can be obtained without impairing the fluorescence intensity and color developability. I. Acid Red 92 and / or C.I. I. Direct Yellow 87 (C.I. Direct Yellow 87) may be included.

  C. above. I. The acid red 92 is preferably contained in an amount of 0.6 to 1.2% by mass, and more preferably 0.6 to 0.9% by mass.

  C. above. I. The direct yellow 87 is preferably contained in an amount of 2 to 4% by mass, and more preferably 2.2 to 3.5% by mass.

Triethylene glycol The ink composition according to the present invention comprises at least triethylene glycol.

  In the present invention, the triethylene glycol is preferably contained in an amount of 0.4 to 3.4% by mass, and more preferably 0.5 to 2.0% by mass with respect to the ink composition. By setting it within this range, an ink composition excellent in clogging recovery can be obtained without impairing the fluorescence intensity and the color developability.

  In the present invention, C.I. I. The content ratio of Acid Red 52 and the triethylene glycol is 1: 5 to 1:23, and more preferably, the content ratio is 1:10 to 1:23. By setting it within this range, a recorded matter having good light resistance can be obtained without impairing the fluorescence intensity and color developability.

<Water and other ingredients>
In the ink composition according to the present invention, water preferably contains water as a main solvent, and it is more preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water. preferable. In particular, it is preferable to use water 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 composition.

  The ink composition according to the present invention preferably comprises a water-soluble organic compound. The water-soluble organic solvent is preferably a low-boiling organic solvent, and examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, iso-butanol, Examples include n-pentanol. A monohydric alcohol is particularly preferable. The low boiling point organic solvent has an effect of shortening the drying time of the ink. The amount of the low-boiling organic solvent added is preferably 0.1 to 30% by mass of the ink, more preferably 5 to 10% by mass.

  According to a preferred embodiment of the present invention, the ink composition according to the present invention further comprises a wetting agent composed of one or more kinds of high-boiling organic solvents. Preferred examples of the high boiling point organic solvent agent include ethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, Polyhydric alcohols such as trimethylolpropane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, Triethylene glycol Of polyhydric alcohols such as monoethyl ether, triethylene glycol monobutyl ether, hexaethylene glycol monoethyl hexyl ether (manufactured by Nippon Emulsifier Co., Ltd .: New Coal 1006), tetraethylene glycol monoethyl hexyl ether (manufactured by Nippon Emulsifier Co., Ltd .: New Coal 1004) Examples include alkyl ethers, urea, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone. Preferred are polyhydric alcohol alkyl ethers.

  In the present invention, as preferred embodiments of polyhydric alcohol alkyl ethers, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, hexaethylene glycol monoethyl hexyl ether, Tetraethylene glycol monoethylhexyl ether can be used alone or in combination. More preferably, a combination of hexaethylene glycol monoethyl hexyl ether and triethylene glycol monobutyl ether or tetraethylene glycol monoethyl hexyl ether and triethylene glycol monobutyl ether is used. By adding these polyhydric alcohol alkyl ethers in combination, it is possible to obtain an ink composition excellent in terms of permeability and stability of the ink composition in a high temperature environment. The alkyl ethers of these two kinds of polyhydric alcohols can be added at various ratios, but are preferably added at a ratio of 1: 1 to 1: 3.

  The addition amount of these high-boiling organic solvents is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass. By setting the addition amount of the high-boiling organic solvent in the above range, a fluorescent ink composition having both better fluorescence intensity and color developability can be obtained. Further, the total content of tetraethylene glycol monoethylhexyl ether and triethylene glycol monobutyl ether is 1 to 6% by mass in the ink composition, and the total content of hexaethylene glycol monoethylhexyl ether and triethylene glycol monobutyl ether is The ink composition preferably contains 1 to 10% by mass.

  Furthermore, according to a preferred aspect of the present invention, the ink composition according to the present invention preferably contains a sugar, a tertiary amine, an alkali hydroxide, or ammonia. With these additions, coloring materials do not aggregate or increase in viscosity even during long-term storage, providing excellent storage stability, and fluidity and re-dispersion even when left open (in contact with air at room temperature) The ink composition is maintained for a long time, and further, the ink composition has high ejection stability without clogging of the nozzles during printing or restarting after printing interruption.

The sugars that can be added to the ink composition according to the present invention include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), and polysaccharides, preferably glucose, mannose, fructose, ribose, Examples include xylose, arabinose, galactose, aldonic acid, glucitol, (sorbit), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature, such as alginic acid, α-cyclodextrin, and cellulose. The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above (for example, sugar alcohol (general formula HOCH ₂ (CHOH) _n CH ₂ OH (where n represents an integer of 2 to 5)). ), Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thio sugars, etc. Particularly preferred are sugar alcohols, and specific examples thereof include maltitol, sorbit and the like.

  The content of these saccharides is in the range of 0.1 to 40% by mass, more preferably 1 to 30% by mass in the ink composition.

  Examples of the tertiary amine that can be added to the ink composition according to the present invention include trimethylamine, triethylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, triisopropenolamine, and butyldiethanolamine. These may be used alone or in combination. The amount of these tertiary amines added to the ink composition of the present invention is 0.1 to 10% by mass, more preferably 0.5 to 5% by mass.

  The alkali hydroxide that can be added to the ink composition according to the present invention is potassium hydroxide, sodium hydroxide, or lithium hydroxide, and the amount added to the ink composition of the present invention is 0.01 to 5% by mass. Preferably, it is 0.05-3 mass%.

  The ink composition of the present invention can further contain a surfactant. Examples of surfactants include anionic surfactants (eg, sodium dodecyl benzene sulfonate, sodium laurate, ammonium salts of polyoxyethylene alkyl ether sulfates), nonionic surfactants (eg, polyoxyethylene Alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, etc.) and acetylene glycols (olefin Y and surfinol 82, 104) 440, 465, and 485 (all manufactured by Air Products and Chemicals Inc.) and Olfin PD002W (manufactured by Nissin Chemical Industry Co., Ltd.)). These can be used alone or in combination of two or more. Preferably, Olfine PD002W is used.

  The ink composition according to the present invention may contain a pH adjuster, a preservative, a fungicide, a phosphorus-based antioxidant, and the like as necessary. Examples of preferable preservatives include proxel CRL, proxel BDN, proxel GXL, proxel XL-2, proxel IB, and proxel TN.

Inkjet Recording Method An inkjet recording method using an ink composition according to the present invention is a method in which droplets of an ink composition are ejected, and the droplets are attached to a heated recording medium for printing. As an example of a method for ejecting ink composition droplets, for example, an electrostrictive element is used to convert an electrical signal into a mechanical signal, and ink stored in the nozzle head portion is intermittently ejected onto the surface of the recording medium. A method of recording characters and symbols, ink heated in the nozzle head portion is heated rapidly at a location very close to the discharge portion, bubbles are generated, and the ink is intermittently discharged by the volume expansion caused by the bubbles, and characters are printed on the surface of the recording medium. And a method of recording symbols. According to a preferred embodiment of the present invention, an ink set comprising the ink composition according to the present invention is preferably used in an ink jet recording method using an electrostrictive element. The ejection of the ink composition droplets is preferably performed by a recording head that ejects ink droplets using the mechanical action of the piezoelectric element.

  The recorded matter recorded on the recording medium using the ink composition according to the present invention exhibits an image having good light resistance without impairing the fluorescence intensity and color developability.

  Various recording media can be used, and examples thereof include envelopes, ink jet dedicated paper (matte paper, glossy paper, etc.), plain paper, printing paper, and films. In particular, an envelope is preferable.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Preparation of Ink Composition Each ink was prepared by mixing each component according to the composition shown in Table 1 below and filtering through a 10 μm membrane filter. The numerical values in Table 1 represent the content (mass basis%) in the ink. In Table 1, EDTA represents disodium ethylenediaminetetraacetate, PD002W represents Orphine PD002W (manufactured by Nissin Chemical Industry), and Proxel XL2 represents 1,2-dibenzisothiazolin-3-one (manufactured by Avecia). The “remaining amount” indicating the amount of water and the amount of water, together with the components other than water, indicates the amount that is 100% in total.

Evaluation methods
Evaluation of color development Using an ink jet printer MJ-8000C (manufactured by Seiko Epson Corporation), a 100% Duty solid pattern was printed on a Script DL envelope at a resolution of 360 dpi. The printed matter was allowed to stand for 24 hours in an environment of 24 ° C., and then the OD value (ODm) of the solid portion was measured using a Gretag densitometer (manufactured by Gretag Macbeth), and evaluated according to the following evaluation criteria.
A: When OD value is 0.8 or more B: When OD value is less than 0.8 Evaluation results are shown in Table 2 and Table 3 below.

Evaluation of fluorescence intensity Using an inkjet recording apparatus MJ-8000C (manufactured by Seiko Epson Corporation) having an on-demand type multi-recording head that discharges each ink composition by applying thermal energy corresponding to the recording signal to the ink, Script A 100% Duty solid pattern was printed on the DL envelope made of the product, and the fluorescence intensity was measured under the following conditions using a fluorimeter (F-4500) manufactured by Hitachi, Ltd. The measurement conditions were such that the excitation wavelength was 365 nm, the fluorescence intensity at the maximum fluorescence wavelength between 550 nm and 650 nm was measured, and evaluated according to the following evaluation criteria.
A: When fluorescence intensity is 300 or more B: When fluorescence intensity is 260 or more and less than 300 C: When fluorescence intensity is less than 260 Evaluation results are shown in Tables 2 and 3 below.

Evaluation of nozzle clogging recovery performance Using ink jet printer PM-A750 (manufactured by Seiko Epson Corporation), the head is filled by repeating the cleaning of each ink, and it is confirmed by printing that the ink is discharged from each nozzle. And left in an environment of 40 ° C. for 1 month. After leaving, the determination was made based on the following evaluation criteria from the number of cleaning operations required until the printer was turned on and all nozzles could be ejected.
○: No cleaning Δ: Cleaning once ×: Cleaning twice or more Evaluation results are shown in Table 2 and Table 3 below.

Claims (4)

C. I. An ink composition comprising at least Acid Red 52 and triethylene glycol,
C. above. I. The ink composition whose content ratio of Acid Red 52 and the said triethylene glycol is 1: 5-1: 23.   C. above. I. The ink composition according to claim 1, wherein the acid red 52 is contained in an amount of 0.05 to 0.2% by mass with respect to the ink composition.   The ink composition according to claim 1, wherein the triethylene glycol is contained in an amount of 0.4 to 3.4 mass% with respect to the ink composition.   An inkjet recording method for performing printing by discharging droplets of an ink composition and attaching the droplets to a recording medium, wherein the inkjet composition uses the ink composition according to any one of claims 1 to 3. Recording method.