JPH03229770A - Recording fluid - Google Patents

Abstract

PURPOSE:To obtain a recording fluid free from discoloration and fading even when in a room or near a copying machine and improved in long-term shelf stability by using a recording agent comprising a specified compound, water, and a water-soluble organic solvent as the constituents. CONSTITUTION:0.5-20wt.% recording agent comprising a compound of formula I [wherein M is a divalent metal; S is a sulfo group, or an alkali metal salt or ammonium salt thereof; l is 1 to 2; R1 is H, alkyl(amido) or sulfo; R2 is (optionally sulfo- or alkoxy-substituted) phenoxy, anilino or group of formula III; m is 2 to 6; R3 is -OH, -NR4R5 or alkoxy; R4 and R5 are each a group of formula IV or V; n is 0 to 4; R6 is H, methyl of methylol; R7 is (optionally sulfo- or alkoxy-substituted)phenylsulfonyl or phenylacetyl; Q is a group of formula VI or VII; R8 to R14 are each R1] is mixed with 10-90wt.% water, 5-95wt.% water-soluble organic solvent, and if necessary, a viscosity modifier, a surface active agent, a surface tension modifier, a pH adjustor, a mildewproofing agent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording liquid suitable for use in an inkjet system or a writing instrument in which recording is performed by ejecting droplets from an orifice of a recording head.

(Prior art and its problems) Various types of inkjet recording methods are being actively researched because they generate less noise (and can perform high-speed recording on plain paper without requiring special fixing). There is.

The recording liquid used in these inkjet recording methods must have physical properties such as viscosity and surface tension within appropriate ranges, must not clog the fine ejection openings (orifices), and must have a clear color tone and a sufficiently high It is required to have certain characteristics such as providing a recorded image of density and not causing changes in physical properties or precipitation of solid content during storage.

In addition to these properties, it also has the ability to record without limiting the type of recording material such as paper, has a high fixing speed to the recording material, and has excellent weather resistance, water resistance, and abrasion resistance. It is also required to have properties such as high resolution and the ability to provide images with excellent resolution.

A recording liquid suitable for an inkjet recording method is basically composed of a dye as a recording agent and its solvent. Selecting a dye so that the recording liquid has the above characteristics is an extremely important technique in this technical field.

In particular, the stability of recorded images over time is important, and many studies have been conducted on photofading, and improvements are being made gradually.In particular, metal-containing azo dyes are relatively stable against light. It is known.

However, when images recorded using such metal-containing dyes are displayed indoors or the like, there is a phenomenon in which the images fade even though they are hardly exposed to strong light. This phenomenon is more noticeable in the vicinity of a copying machine, where the sharp color tone changes or the print density decreases.As a result, the quality of the image deteriorates significantly, so it must be resolved. That's a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a self-recording liquid that does not cause discoloration or fading even indoors or near a copying machine, and that provides recorded images that can withstand long-term storage. Our goal is to provide the following.

Another object of the present invention is to provide a recording liquid that improves the water resistance of recorded images. Images recorded using a water-soluble recording liquid are water-soluble and therefore have poor water resistance, and when a printed matter gets wet with water, the image may disappear or smudge, resulting in a decrease in image quality.

In general, when direct dyes are used as recording agents, they have the advantage of being difficult to remove even when wet with water because they have a strong dyeing property on the cellulose fibers of paper, and are less likely to bleed. The higher the linearity of the dye, the easier it is to be adsorbed on cellulose fibers, and therefore dyes with longer chains often have better water resistance.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a recording liquid containing a recording agent, water, and a water-soluble organic solvent as essential components, characterized in that the recording agent contains a compound having a structure represented by the following general formula (A). It is a liquid.

(However, in the formula, X represents the following structure, -NH-C"\-R3 ]12M represents a divalent metal, S represents a sulfonic acid group or its alkali metal salt to ammonium salt, and ρ represents l or 2 , R3 is a hydrogen atom, an alkyl group, a sulfonic acid group, or an alkylamido group, and R2 is a phenoxy group, anilino group, or -NH(CHa
)-NH-R7 (m is an integer of 2 to 6), R3 is -0H
1-NR4R% or an alkoxy group, R4 and R5 are each independently -(CHaC)1.0). -R6 or -(C
H2CHOH) , -R6 (n is an integer from 0 to 4),
R6 is a hydrogen atom, methyl group or methylol group.

R1 is a phenylsulfonyl group or a phenylacetyl group which may be substituted with a sulfonic acid group or an alkoxy group, and Q
R8 to R14 each independently represent any of the atomic groups represented by R1. ) (Function) As a result of intensive research, the inventors of the present invention discovered that the cause of the above-mentioned fading phenomenon is due to oxidizing gases such as ozone, nitrogen gas, and sulfur gas present in the air. Ta.

Therefore, in order to improve such drawbacks, detailed research on metal-containing dyes was conducted, and it was found that a recording liquid containing a disazo type dye having the molecular structure represented by the general formula (A),
It was discovered that not only light fastness but also good recorded images that do not discolor or fade even in an oxidizing gas atmosphere such as ozone can be obtained, and the recorded images have good water resistance. It's arrived.

(Preferred Embodiment) The dye represented by the general formula (A), which mainly characterizes the present invention, may be any dye as long as it is included in the general formula, but preferred specific examples include the following No. , No. 1 to No. 9. still,
M in the general formula (A) may be other divalent metals such as nickel and cobalt in addition to copper as exemplified below.

No, 1 N.

No.

No.

N.

No.

No.

N.

9 The content of the above-mentioned dye in the recording liquid of the present invention is determined depending on the type of liquid medium components, the properties required of the recording liquid, etc., but is generally determined as a percentage by weight based on the total weight of the recording liquid. 0.5 to 20%, preferably 0.5 to 15%
, more preferably in the range of 1 to 10%. Of course,
These specific dyes can be used alone or as a mixture, and can also be used in combination with various dyes such as other direct dyes and acid dyes.

A suitable solvent for use in the recording liquid of the present invention is water or a mixed solvent of water and a water-soluble organic solvent, and particularly preferred is a mixed solvent of water and a water-soluble organic solvent, which is a water-soluble solvent. It contains polyhydric alcohol, which has the effect of preventing the recording liquid from drying, as an organic solvent. Further, the water is not ordinary water containing various ions (it is preferable to use deionized water).

Examples of water-temperature organic solvents used in combination with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ee-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol. Alkyl alcohols with 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketone or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol Class: alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexandriol, thiodiglycol, hexylene glycol, diethylene glycol, etc. Glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether; N-methyl-2-pyrrolidone;
Examples include 1,3-dimethyl-2-imidazolidinone.

Among these poly(water-soluble organic solvents), polyhydric alcohols such as diethylene glycol, lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether, nitrogen-containing complexes such as N-methyl-2-pyrrolidone, etc. Cyclic ketones are preferred.Polyhydric alcohols are highly effective as wetting agents to prevent nozzle clogging, as the water in the recording liquid evaporates and the dye precipitates. Therefore, it is preferable.

The content of the water-soluble organic solvent in the recording liquid is generally in the range of 5 to 95% by weight, preferably 10 to 80%, more preferably I5 to 50%, based on the total weight of the recording liquid. .

The water content at this time is determined within a wide range depending on the type of solvent component, its composition, and the desired characteristics of the recording liquid, but it is generally 10 to 90% of the total weight of the recording liquid.
, preferably within the range of 10 to 70%.

The recording liquid of the present invention prepared from such components has excellent recording properties (signal response, stability of droplet formation, ejection stability) as a recording liquid for writing instruments or a recording liquid for so-called inkjet recording. , long-term continuous recording performance, ejection stability after long-term recording pauses), storage stability, fixability to recording materials,
Alternatively, the recorded image has excellent, well-balanced color clarity, light resistance, weather resistance, etc. In order to further improve such properties, various conventionally known additives may be added.

For example, viscosity regulators such as polyvinyl alcohol, cellulose, and water-soluble resins; various cationic, anionic, or nonionic surfactants; surface tension regulators such as diethanolamine and triethanolamine; pH regulators using buffer solutions; and mold prevention agents. Agents, etc. can be mentioned.

Further, in order to prepare a recording liquid used in an inkjet method of charging the recording liquid, a resistivity adjusting agent such as inorganic salts such as lithium chloride, ammonium chloride, and sodium chloride is added.

Note that when applied to an inkjet system in which recording liquid is ejected by the action of thermal energy, thermal physical property values (eg, specific heat, coefficient of thermal expansion, thermal conductivity, etc.) may be adjusted.

The recording liquid of the present invention as described above is useful as a recording liquid for recording with various writing implements, recording instruments, etc., and is particularly useful as a recording liquid for inkjet use. The inkjet method may be any method as long as it can effectively remove the recording liquid from the nozzle and apply the recording liquid to the recording material that is the projectile.

(Examples) Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Note that % in the text is based on weight unless otherwise specified.

Example 1 No. 1 dye 3% diethylene glycol 30% ion exchange water (
67% Example 2 No. 2 dye polyethylene glycol (average molecular weight 5% 300) 10% 20% 65% diethylene glycol water Example 3 No. 3 dye N-methyl-2-pyrrolidone diethylene glycol water Implementation Example 4 Seed 4 Dye 3% 15% 15% 67% 2% Triethylene Glycol Water Example 5 Nα5 Dye Ethylene Glycol Water Example 6 Nα6 Dye Diethylene Glycol Ethyl Alcohol Water Example 7 Toru 7 Dye Glycerin Polyethylene Glycol 28 % 67% 7% 40% 53% 4% 20% 5% 71% Diethylene glycol water Example 8 11kt8 dye 6% 5% (average molecular weight 300) l 0% 20% 59% 3% Diethylene glycol 30% ion exchange water ( (hereinafter abbreviated as water) 67% Example 9 Tooth, Dye 9 5% Polyethylene glycol (average molecular weight 300) 10% Diethylene glycol 20% Water
65% The above ingredients are thoroughly mixed and dissolved in a container with a pore size of 0.45LL.
The recording liquid of the present invention was obtained by pressure filtration using a Teflon filter.

Inkjet printer BJ-130 uses these recording liquids as a heat generating element as an ink ejection energy source.
A (manufactured by Canon, number of nozzles: 48) and after printing a solid print of 15 mm x 30 mg+ on the following recording materials A and B, the ozone concentration was increased to 10± as a method to accelerate discoloration and fading.
One print is placed in a light-shielded tank maintained within the 5 ppm range.
When the color difference ΔE"ab of the printed matter before and after the test was measured after being left for 20 minutes (according to JIS Z 8730), the ΔE"ab value was less than 1O in each case, and the degree of discoloration was small (good results). was gotten.

Recording material A: coated paper for inkjet manufactured by Mitsubishi Paper Industries NM Recording material B: specified paper exclusively for Canon's Bixel Pro Recording material C: recommended paper for Canon's NP-6150 Recording material D: 4024 paper manufactured by Xerox Next, do the same When the light resistance of a printed piece made with a recording liquid having the components shown in the example was evaluated using a xenon fade meter at ΔE''1° before and after 96 hours of irradiation, it was 5 or less in all cases, indicating that the degree of discoloration was small. (Good results were obtained.

In addition, in the same manner as above, the printed pieces and characters printed solidly on the recording materials C and D with the recording liquid having the components shown in the examples were immersed in still water for 5 minutes, and then the OD value of the solid printed pieces was determined. The OD residual rate (%) is calculated by dividing the initial OD value of the solid print before dipping.
), the results were 70% or higher in all cases, and no bleeding was observed in the printed characters, indicating good water resistance.

For comparison, a similar water resistance test was conducted on solid and character prints made on recording materials C and D in the same manner as above using a recording liquid with the components shown in the comparative example.
In all cases, when the OD residual rate was 50% or less, the characters were significantly faded and difficult to read.

Comparative Example I C,1, Reactive Black 31 3% diethylene glycol 30% water
67% Comparative Example 2 Dye with the following structural formula 5% polyethylene glycol (average molecular weight 300) diethylene glycol water 10% 20% 65% Comparative Example 3 Dye with the following structural formula N-methyl-2-pyrrolidone diethylene glycol water 3% 15% 15% 67% Comparative Example 4 Dye with the following structural formula, triethylene glycol water 2% 28% 70% Comparative Example 5 Dye with the following structural formula, ethylene glycol water Comparative Example 6 Dye with the following structural formula, diethylene glycol ethyl alcohol water 7% 40% 53% 4 % 20% 5% 71% (Effects of the Invention) As described above, the recording liquid of the present invention is suitable for inkjet recording, writing instruments, and the like.

In particular, when used for inkjet recording, not only recording characteristics (ejection stability, long-term continuous recording), storage stability, but also light resistance of recorded images, ozone, No. 2, SO, etc.
It is extremely stable against oxidizing gases such as, and is extremely useful, as it can produce prints with excellent water resistance, especially on plain paper.

Claims (1)

[Claims] (1) A recording liquid containing a recording agent, water, and a water-soluble organic solvent as essential components, characterized in that the recording agent contains a compound having a structure represented by the following general formula (A). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) (However, in the formula, Metal salt to ammonium salt, l is 1 or 2, R_1 is a hydrogen atom, alkyl group, sulfonic acid group, or alkylamido group, R_2 is a phenoxy group or anilino group that may be substituted with a sulfonic acid group or an alkoxy group. or -NH(C
H_2)_mNH-R_7 (m is an integer from 2 to 6), R
_3 is -OH, -NR_4R_5 or an alkoxy group,
R_4 and R_5 are each independently −(CH_2CH_2
O)_n-R_5 or -(CH_2CHOH)_n-R
_6 (n is an integer of 0 to 4), R_6 is a hydrogen atom, methyl group or methylol group, R_7 is a phenylsulfonyl group or phenylacetyl group which may be substituted with a sulfonic acid group or an alkoxy group, Q is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R_8 to R_1_4 each independently represent one of the atomic groups shown by R_1. )