JPS624763A - Recording fluid - Google Patents

Abstract

PURPOSE:To provide a recording fluid which as excellent stability, long-term shelf stability and fixation to agents to be recorded, does not cause clogging and is suitable for use in ink jet recording, containing a recording agent contg. a dye and a solvent for use in dissolving or dispersing it as main components. CONSTITUTION:A recording agent (A) which is a component capable of forming an image contg. 0.05-1.0% (by weight based on the entire quantity of recording soln; the same applied hereinbelow) at last one dye of the formula (wherein 45mol% or less of M is H and 55 mol% or more of M is Li or K) is dissolved or dispersed in a solvent system (B) consisting of 10-80% polyhydric alcohol(a 2-6C alkylene glycol), optionally, 10-70% water-soluble or. solvent (e.g. methyl alcohol) and 30-90% water.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to a novel recording liquid used for ink recording, which does not cause clogging in the recording means, and in particular, to a new recording liquid that does not cause clogging of the recording means, and in particular, a new recording liquid that is used for ink recording. The present invention relates to a recording liquid suitable for a recording method in which recording is performed by ejecting the recording liquid from an ejection port (ejection orifice) and flying it as droplets.

[Prior Art] Traditionally, writing instruments (fountain pens, felt pens, etc.) used as recording means for recording on recording materials such as paper have used inks made by dissolving various dyes in water or organic solvents. It is used.

In addition, in the so-called inkjet recording method, in which recording is performed by ejecting the liquid in the recording head from the ejection orifice using vibrations by a piezo vibrator or electrostatic attraction due to the application of high voltage, various dyes are mixed with water or organic It is known that a composition dissolved in a solvent or the like is used. However, compared to inks for stationery such as general fountain pens and felt-tip pens, inkjet recording liquids require more stringent conditions in many characteristics.

In such an inkjet recording method, recording is performed by causing droplets of a recording liquid called ink to fly and attaching them to a recording material. The basic components of such a recording liquid include a recording agent (dye or pigment is used) and a liquid medium for dissolving or dispersing it (water or various organic solvents or mixtures thereof are used), and various additives are added as necessary. Additives are added.

Conventionally, as this type of recording liquid, for example, Japanese Patent Publication No. 50-83
Publication No. 61, Special Publication No. 51-40484, Special Publication No. 5
As shown in Japanese Patent Publication No. 2-13126, Japanese Patent Publication No. 52-13127, and Japanese Patent Application Laid-Open No. 50-95008, there are known dyes or pigments in which various dyes or pigments are dissolved or dispersed in aqueous or non-aqueous solvents. .

Preferred conditions for this type of recording liquid include: 1) liquid physical properties (viscosity, surface tension, conductivity, etc.) that match the ejection conditions (piezoelectric element drive voltage, drive frequency, orifice shape and material, orifice diameter, etc.); have.

2) Stable and free from clogging during long-term storage.

3) Fixation is fast on the recording material (paper, film, etc.), and the dot periphery is smooth and there is little bleeding.

4) The color tone of the printed image is clear and the density is high.

5) The printed image has excellent water resistance and light resistance.

6) The recording liquid should not corrode surrounding materials (coils, connecting tubes, sealing materials, etc.).

7) It must be safe in terms of odor, toxicity, and flammability.

etc.

It is quite difficult to simultaneously satisfy the above characteristics, and the prior art described above was unsatisfactory in this respect.

A recording liquid suitable for recording for such purposes is basically composed of a dye and its solvent as described above, so the characteristics of the recording liquid described above depend on the inherent properties of the dye and the components used as the liquid medium. Much depends on nature.

Therefore, selecting a dye and a liquid medium so that the recording liquid has the above-mentioned properties is an extremely important technique in this technical field.

Among these, there is no known recording liquid that fully satisfies all of the above-mentioned characteristics among recording liquids using yellow dye.

That is, mainly to improve the effect of preventing clogging of the recording liquid discharge port due to the precipitation of inorganic salts, the stability of the recording liquid, and especially the effect of preventing corrosion of the metal components of the writing instrument.
For example, Na C/, Na 2 contained in the dye
Inorganic salts such as 804, ions such as Ca"+, etc. are removed by ultrafiltration, treatment with ion exchange resins, treatment with various organic solvents and agents, or a combination of these with treatments such as salting out and acid precipitation. For example, the amount of NaC1! in the dye is reduced to 5% by weight or less, and the amount of Na2SO4 in the dye is reduced to 1% by weight or less.

[Problem that the invention seeks to solve]

However, when such treatment is applied to yellow dyes such as C,1, Direct Yellow 86 and its derivatives, the chemical and physical properties of the dye itself change.
In particular, contrary to the above-mentioned purpose, it has been found that the stability and long-term storage stability of recording liquids using such dyes are considerably deteriorated.

Conventionally, water or a mixture of water and various water-soluble organic solvents have been used as the liquid medium for the recording liquid, but a liquid that can form a recording liquid that satisfies relatively all of the above characteristics of the recording liquid has been developed. water and ethylene glycol as medium;
A mixture with glycols such as diethylene glycol is preferably used, and this is thought to be due to a significant decrease in the solubility of the yellow dye after the above treatment in such a liquid medium.

As a result of extensive studies, the present invention has been found to be suitable for recording liquids used for such purposes, and in particular has excellent solubility in liquid media mainly consisting of a mixture of water and glycols, which may cause clogging, etc. It was completed by finding a dye with a low content of inorganic salts.

The dye having the structure represented by the general formula (A) has hue, light resistance,
Although it was attracting attention as having excellent basic properties such as water resistance, it had defects in solubility in the recording liquid solvent and storage stability of the recording liquid, so the reality was that it was put on hold for practical use. Ta.

These problems could be solved by the improvements made by the present invention.

[Means for solving problems]

The above object is achieved by the present invention as follows.

That is, the recording liquid of the present invention is a recording liquid mainly composed of a recording agent which is a component forming a grain, and a saliva medium containing at least water and glycols for dissolving or dispersing this recording agent. The recording agent contains at least one dye represented by the following general formula (A); (wherein represents at least one element selected from M, H, Li and K); 55 mol% or more of the total amount of M represented in the general formula (A) is Li or K.
It is characterized by one type selected from any of the following.

[For production]

The liquid medium constituting the recording liquid of the present invention preferably contains water in an amount equal to or less than 80% by weight of the core liquid medium.

The recording liquid of the present invention has the above general formula (
A liquid medium containing at least one of the dyes represented by A), at least water, and glycols, which are particularly effective in preventing clogging, is used.

Examples of glycols that can be contained in the liquid medium constituting the recording liquid of the present invention include polyethylene glycol,
Polyalkylene glycols such as polypropylene glycol; ethylene glycol, propylene glycol, butylene glycomyl, triethylene glycol, 1,2.
Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as 6-hexandriol, thiodiglycol, hexylene glycol, diethylene glycol:
Glycerin; Examples include lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether, and one or more of these can be used as a liquid medium component. can be used.

The content of the above-mentioned glycols in the recording liquid is generally 10 to 70% by weight based on the total weight of the recording liquid, preferably 2.
0 to 60X1), preferably 25 to 40X.

In addition to the above-mentioned glycols as liquid medium components, the recording liquid of the present invention may optionally contain a water-soluble organic solvent such as methyl alcohol, ethyl alcohol, or n-propyl alcohol in order to improve the properties of the recording liquid. , isopropyl alcohol, n-methyl alcohol, 5ea-7′ methyl alcohol, tert-7′ methyl alcohol, isobutyl alcohol, and other carbon Al-4 alkyl alcohols;
Amides such as dimethylformamide and dimethylacetamide; ketone alcohols such as acetone and diacetone a/l/co/l/; ethers such as tetrahydrofuran and dioxane; N-methyl-2-pyrrolidone and 1,3-dimethyl One or more types of nitrogen-containing heterocyclic ketones such as -2-imidazolidinone may be added.

Generally, the content of water-soluble organic solvents including the above-mentioned glycols in the recording liquid is 1 in fX based on the total weight of the recording liquid.
The range is 0 to 70X, preferably 20 to 60%, more preferably 30 to 55%.

The water content at this time is determined within a wide range depending on the type of solvent component, its composition, or the desired properties of the recording liquid, but is generally 30 to 90% of the total weight of the recording liquid.
%, preferably 40-80%, more preferably 45-8
It is assumed to be in the ON range.

The dye used in the recording liquid of the present invention has the general formula (A).
It is composed of at least the types of dyes shown in the following, and shows good solubility in a saliva medium containing water and glycols having the composition described later.

Generally, the solubility of the dye represented by the general formula (A) in water, which is contained as a component of the liquid medium, changes greatly depending on the ratio of Li or K to M in the dye. Therefore, in the dye used in the recording liquid of the present invention using a liquid medium having the above composition, 55 mol% or more of the total amount of M contained in the dye should be one selected from Li or FiK. is desirable.

The dye that can form the recording liquid of the present invention can be produced using C,1, Direct Yellow 86 and its derivatives as starting materials.

That is, a method using a yellow dye consisting of C,1, Direct Yellow 86 and its derivatives, ultrafiltration, treatment with an ion exchange resin, treatment with various organic solvents, or a combination of these with treatments such as salting out and acid precipitation. By N
aC/, Na2804.

Inorganic components such as LiOH, KOH, and calcium ions are removed, and then the content of Li or iK, which is the target element in the dye molecule, is determined by various analytical methods. LiOH or KO depending on the purpose
By adding H, etc. to form salt and replenishing the shortage, each desired component (in the case of Li, K
) can be generated by controlling the ratio of M to the total amount to a predetermined value.

In the present invention, the target element (for example, Li.

The ratio of K) to the total amount of M is measured using, for example, atomic absorption spectrometry.

In the recording liquid of the present invention, the content of the dye represented by the general formula (A) is determined depending on the type of liquid medium, the characteristics required of the recording liquid, etc. 0.05 to 1% by weight based on the total weight of the liquid. ON, preferably 0.05
The range is preferably 0.05 to 4%, more preferably 0.05 to 4%. Of course, these dyes can be used alone or in combination of two or more, or in combination with other direct dyes or acid dyes.

When a recording liquid prepared from such components is used as a recording liquid for writing instruments such as fountain pens, water-based ballpoint pens, felt pens, etc., it has poor fixability to recording materials, light resistance, Not only does it have excellent weather resistance and water resistance, but it also has a suitable combination of liquid medium and dye. It is an excellent recording liquid with recognized stability, no precipitation of dye at the recording liquid discharge port of the pen tip, etc. after long-term storage, and no clogging.

Also, even when used for inkjet recording,
Recording characteristics (signal response, stability of droplet formation, ejection stability, long-term continuous recording performance, ejection stability after a long period of recording interruption), storage stability, fixation to recording material, etc. It has excellent, well-balanced properties such as light resistance, weather resistance, water resistance, etc. of recording materials.Among these properties, it has excellent stability and long-term storage, and has excellent It has clear advantages over conventional recording liquids in that it does not cause clogging.

The recording liquid of the present invention may further contain various conventionally known additives in order to further improve such characteristics. 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 buffers; antifungal agents etc. can be mentioned.

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.

According to the present invention, physical property values such as viscosity and surface tension are within appropriate ranges, and the recording liquid ejection openings such as the nib of a fountain pen or the fine orifice of an inkjet recording device are not clogged and are sufficiently It provides high-density recording materials, does not change physical properties or precipitate solids during storage, can record on a variety of materials without limiting the type of recording material, has a high fixing speed, and is water resistant. A recording liquid is obtained which gives an image with excellent properties, light fastness, abrasion resistance and resolution.

The present invention will be explained in more detail by the following examples.

Examples 1-3 Commercially available dye Kayaku Direct Yellow & Special (C,
1. Direct Yellow 86 (manufactured by Nippon Kayaku Co., Ltd.) 4
00? An aqueous solution is prepared, and hydrochloric acid is added thereto while stirring until a sufficient amount of precipitate is formed (acid precipitation treatment).

The resulting precipitate was taken from house to house, thoroughly washed with water, and dried product A was obtained. The obtained dried product was measured with an atomic absorption spectrophotometer, and the Na
Confirm that there are no errors, or that they are negligible.

Next, the above dried material A is weighed and put into 3 beakers in 102 portions. Each sample in these beakers is sample 1.
．． Il, III. Add lithium hydroxide aqueous solution to each sample while stirring.

In this case, each lithium hydroxide aqueous solution was prepared by dissolving a specified amount of lithium hydroxide in water 2001, and sample I had a concentration of 0.31 F, sample II had a concentration of 0.31 F,
Sample (2) contained 0.2 Of lithium hydroxide.

The aqueous solutions of Samples 1 to 1 were sufficiently stirred, and then dried and powdered to obtain three types of dyes, Taka 1 to 3.

When the amount of Li contained in these /161-3 dyes was measured using an atomic absorption spectrophotometer, it was found that the amount of Li in the total amount of M in the dye structure was
The ratio was as shown in Table 1.

Table 1 Next, each dye in Table 1 was added to a liquid medium having the composition shown below so that the concentration in the recording liquid would be 3%, thoroughly mixed and dissolved. After pressure filtration with a manufactured filter, deaeration treatment is performed using a vacuum pump,
It was used as a recording liquid.

Composition of liquid medium> Ion-exchanged water (hereinafter abbreviated as water) 60 parts by weight Diethylene glycol 40 parts by weight Using each of the three types of recording liquids obtained, an on-demand recording head (on-demand type recording head that ejects the recording liquid by a piezo vibrator) was prepared. Discharge oriice diameter 50 μm 1 Piezo vibrator drive voltage 60V, frequency 4K
Inkjet recording was carried out using a recording apparatus having a high frequency (Hz), and the following items, which had been problematic with conventional recording liquids, were particularly investigated. The results obtained are shown in Table 3.

(T1) Long-term storage stability of recording liquid The recording liquid was sealed in a glass container and stored at -30°C and 60°C for 6 months, and then tested and evaluated to see if precipitation of insoluble matter was observed.

The case where no precipitation of insoluble matter was observed was given as (○), and the case where precipitation of insoluble matter was observed was given as (x).

(T2) Discharge stability: Continuous discharge was performed for 24 hours in an atmosphere at room temperature, 5° C., and 40° C., respectively. Under any conditions, a case where stable high-quality recording was achieved from beginning to end was marked as (○), and a case where it was not possible was marked as (X). Moreover, the intermediate value was defined as (Δ).

(T3) Ejection responsiveness: The recording device was operated after being left for 3 months, and the ejection state in intermittent ejection every 2 seconds before and after being left was examined. If the stable and uniform dispensing condition before being left is also obtained after being left unused (
◎), a slight disturbance in the discharge was observed in the initial stage of operation after being left unused, but a stable and uniform discharge condition was obtained after a few seconds (○), a case in which the stable and uniform discharge condition was maintained before being left unused. The case where it was not obtained later was marked as (x).

(T4) Orifice clogging; After leaving the recording device unattended for 3 months, the orifice tip was observed using a microscope. No clogging was observed (○), and only slight clogging was observed (Δ). ), and the case where the nozzle was completely blocked was defined as (X).

(T5) Quality of recorded images: The recorded images have high density and are clear, and the density decrease is less than 1% after being exposed to indoor light for 3 months, and when immersed in water for 1 minute. (○) indicates that the image has very little blurring, while the recorded image has a high density and is not clear, or the image is clear but the density has decreased after being exposed to indoor light for 3 months. A rating of (x) was given when the image exceeded IX and significant blurring of the image was observed when immersed in water for 1 minute.

(T6) Fixability on various recording materials: After 15 seconds of printing with the recording materials listed in the table below, the printed area was rubbed with a finger to determine the presence or absence of image displacement and bleeding. Excellent fixing performance without image shift, blurring, etc. is shown (○), image shift, blurring, etc. Comparative Examples 1 to 3 In Examples 1 to 3, dried material A was further added to 10? Weigh each sample, place it in three beakers, and add the sample ff,
Let them be V and W.

Each sample was made to contain 0.18 t and 12 t of lithium hydroxide in the same manner as in Examples 1 to 3, respectively, to obtain three types of dyes/164 to 6. These/V,
Table 2 shows the proportions of LL in dyes 4 to 6.

Table 2 Next, recording liquids were prepared in the same manner as in Examples 1 to 3 using each dye i shown in Table 2.

Table 3 shows the results of tests similar to those in Examples 1 to 3 using each of the three types of recording liquids obtained.

Table 3 Examples 4 to 8 The ratio of M to the total amount of M in the dye structure of general formula (A) was changed in the same manner as described in Examples 1 to 3, except that Li was replaced with K. Adjust dye layers 7 to 9 (Table 4)
and the same test as described in the previous example) (Tl~Ts
) was carried out. The results are shown in Table 6.

Table 4 Comparative Examples 4 to 6 Comparative Examples 1 to 3 except that Li'lr was replaced with K
Dyes 410 to 12 were prepared in the same manner as above (Table 5) in which the proportion of Mt to the total Mt in the dye structure was varied, and the same tests (Tl to Ts) as in the previous example were conducted. The results are shown in Table 6.

Table 5 Table 6 Examples 7 to 10 Each of the recording liquids prepared in Examples 1.2 and 4.5 was individually filled into a felt tube, and these recording liquids were used to print medium-quality paper [White Botan]. (trade name), Honshu Paper Industries Co., Ltd.], and the water resistance of the recorded prints was examined. Furthermore, the aging of the felt-tip pens was examined after the caps were scratched off and the pens were left for 24 hours.

All of the recording liquids used in this example had excellent water resistance, and even after being left for 24 hours, no precipitation of dye or the like was observed on the pen tip, indicating good recording performance.

Claims (2)

[Claims] (1) In a recording liquid mainly composed of a recording agent, which is a component for forming an image, and a liquid medium containing at least water and a polyhydric alcohol for dissolving or dispersing the recording agent, recording is possible. As an agent, at least one dye represented by the following general formula (A) ▲Mathematical formula, chemical formula, table, etc.▼ (However, in the formula, M represents an element selected from H, K, and Li) and 55 mol% or more of the total amount of M in the general formula (A) is L.
A recording liquid characterized by being one type selected from either i or K. (2) The recording liquid according to claim 1, wherein the liquid medium contains water in an amount of 80% by weight or less based on the liquid medium.