JP3134629B2 - Inkjet recording liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording liquid used for an ink jet printer.

[0002]

2. Description of the Related Art An ink jet printer ejects ink from minute nozzles to record characters, figures and pictures on paper. Both aqueous and non-aqueous ink jet recording liquids are used for such printers, and basically, it is required to have the following characteristics.

[0003] The ink jet device is stable against long-term storage and does not cause clogging.

[0004] Fixing to an image recording material (paper, film, etc.) is fast and reliable, and the periphery of the dot is smooth and has little blur.

The color tone of the formed recorded image is clear and high in density.

[0006] The formed recorded image is excellent in water resistance and light resistance.

Excellent transparency in color OHP printing and full color printing.

[0008] The recording liquid peripheral material (container, connecting tube, seal material, etc.) must not be affected.

Low odor and toxicity, and excellent in safety such as flammability.

However, water-based inks have low odor and toxicity, and are excellent in safety such as flammability. However, since the coloring materials are only water-soluble dyes, they can be obtained although they have good translucency. The recorded image is inferior in water resistance and light resistance depending on the physical properties of the water-soluble dye. In order to avoid the problem, those using pigments instead of dyes are difficult to disperse finely and uniformly and have poor storage stability because the pigments are insoluble in water. Further, there is a problem that water is easily evaporated and clogging is likely to occur at a discharge portion of the ink jet device. In the case of using only a pigment, it is difficult to obtain good color development due to poor light transmission during color OHP printing or full color printing.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a recording liquid having good dispersibility of a pigment, no occurrence of dry clogging, and excellent storage stability, stability and fixability. The purpose is to provide.

Another object of the present invention is to provide a recording liquid having excellent translucency in color OHP printing or full color printing.

A further object of the present invention is to provide an ink jet recording liquid which can form an excellent recorded image which does not show off when printed at high density.

[0014]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a resin having a boiling point of 150.degree.
A dispersion medium comprising the above non-aqueous solvent, 0.5 to 10% by weight of a pigment, 0.5 to 10% by weight of a dye, 0.01 to
And soluble in the resin to the dispersion medium of 10% by weight, 0.001
The present invention relates to an ink jet recording liquid containing 5% by weight of borneols . In addition, the present invention has a boiling point of 150 ° C.
A dispersion medium comprising the above non-aqueous solvent, and 0.5 to 10 weight
% Pigment, 0.5 to 10% by weight of dye, 0.01 to
10% by weight of a resin soluble in the dispersion medium,
A 5% by weight of alginate and no water
It relates to a recording liquid for ink jet. Also, the present invention
A dispersion medium comprising a non-aqueous solvent at 150 ° C. or higher,
10% by weight pigment, 0.5 to 10% by weight dye,
0.01 to 10% by weight of a resin soluble in the dispersion medium, and 0.1 to 10% by weight.
001-5% by weight alginate and 7-50% by weight
The present invention relates to an inkjet recording liquid containing water.

According to the present invention, a recording liquid comprising the above composition is a homogeneous solution in which a pigment and a dye are dispersed and dissolved, and the other components are dissolved or compatible with each other. Excellent, especially by including at least one kind of the above-mentioned additives in a predetermined amount, in addition to the above effects, it is possible to obtain a recording liquid having excellent pigment dispersibility, bleeding, excellent recorded image without show-through Can be formed.

The ink jet recording liquid of the present invention comprises at least a dispersion medium, a pigment, a dye, a resin and an additive.

As a dispersion medium, a non-aqueous solvent is used. Non-aqueous solvents are solvents other than water. Among these non-aqueous solvents, those having a boiling point of 150 ° C. or higher, preferably 180 ° C. or higher are used. If the boiling point is lower than 150 ° C., problems such as poor dispersion, precipitation of agglomerates, and clogging of nozzles are likely to occur because the evaporation rate is high. When water is added to the recording liquid, it is preferable to use a non-aqueous solvent compatible with water. Specifically, (mono, di, tri, tetra)
Alkyl ethers of alkylene glycols, for example,
Ethylene glycol monoalkyl ether (bp 150
To 250 ° C.), diethylene glycol monoalkyl ether (bp 150 to 250 ° C.), triethylene glycol monoalkyl ether (bp 249 to 300 ° C.), propylene glycol monoalkyl ether (bp 190
To 250 ° C), tripropylene glycol monoalkyl ether (bp 243 to 300 ° C), (mono, di, tri) alkylene glycol (bp 150 to 300 ° C)
Examples thereof include the above-mentioned alkyl ether acetates of alkylene glycol (bp 150 to 300 ° C), pyrrolidones such as 2-pyrrolidone (bp 245 ° C), N-methylpyrrolidone (bp 202 ° C), and mixtures thereof.

In addition, heterocyclic alcohols, phenols, pyrrolidones, ester solvents (adipate, azelate, sebacate, maleate, fumarate, phosphate, ricinoleate, heterocyclic ester) and the like having a boiling point of 150 ° C. or more A thing may be used.

Among these, (mono, di, tri) ethylene glycol monobutyl ether, (mono, di, tri)
Propylene glycol monobutyl ether, butyl cellosolve, and 2-pyrrolidone are preferred in terms of pigment dispersibility, resin solubility, printability, ink jet head maintainability, and the like.

The above non-aqueous solvent is desirably contained in the recording liquid in an amount of 55% by weight or more when water is not added to the recording liquid, and preferably in an amount of 40% by weight or more in the recording liquid when water is added.

In the present invention, it is preferable to add water. By using a non-aqueous solvent and water compatible with water, the drying speed of the ink when printing is fast,
In addition, bleeding of the ink can be prevented. The amount of water to be added is 7 to 50% by weight, preferably about 10 to 45% by weight of the recording liquid composition. If it is less than 7% by weight, the effect of addition cannot be obtained. If it is 50% by weight or more, the fixing speed of the recording paper becomes slow, and there is a possibility that the recording paper is offset on another paper. Further, the addition of water is necessary for the jet ink of the bubble jet type, and is useful when the recording liquid may be ignited.

As the pigment for composing the recording liquid of the present invention, any of various organic or inorganic pigments including conventionally known pigments can be used. For example, azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigo, benzidine, thioindico, perinone, perylene, isoindolenone, titanium oxide, cadmium, iron oxide, carbon black, etc. Can be mentioned.

The materials having various properties as pigments usable in the present invention are shown below by color index (CI) numbers.

C. I. As yellow pigments, 13, 24,
86, 93, 94, 108, 109, 110, 117,
125, 137, 138, 147, 153, 154, 1
66, 168 and the like. C. I. Examples of the orange pigment include 36, 43, 51, 55, 59, 61 and the like. C. I. As the red pigment, 97, 122, 1
23, 149, 168, 177, 178, 180, 18
7, 190, 192, 209, 215, 216, 21
7, 220, 223, 224, 226, 227, 22
8, 240 and the like. C. I. As violet pigments, 19, 23, 29, 30, 37, 40, 50
And the like. C. I. As blue pigments, 15, 1
5: 1, 15: 3, 15: 4, 15: 6, 22, 60,
64 and the like. C. I. As the green pigment, 7,
36 and the like. C. I. As brown pigment,
23, 25, 26 and the like. C. I. Examples of the black pigment include 7.1.

These pigments can be used in a state of being dissolved or insoluble in the above-mentioned solvent, but are generally not dissolved. These pigments have a volume average particle size of 0.001 to
30 μm, preferably 0.001 to 10 μm, more preferably 0.01 to 4 μm is used. If it is larger than 30 µ, the dispersion stability deteriorates, clogging at the nozzles and aggregation during storage of the ink occur, and if it is smaller than 0.001 µ, the dispersibility becomes poor, the thixotropy increases, and the print density becomes poor.

As the dye for composing the recording liquid of the present invention, various kinds of natural and synthetic dyes including those conventionally known can be used. For example, nitroso, nitro, azo, stilbene, diphenylmethane, triarylmethane, xansen, acridine, quinoline, methine, polymethine, thiazole, indamine,
Examples of the dye include indophenol, azine, oxazine, thiazine, sulfide, aminoketone, oxyketone, anthraquinone, indigoid, and phthalocyanine dyes.

The above pigment is used in the recording liquid composition in an amount of 0.5 to 1
0% by weight, and 0.5 to 10% by weight of the dye. It is desirable to use the pigment and the dye in a weight ratio of 1: 8 to 8: 1. Also, by combining the above pigment and dye,
1 to 20% by weight, preferably 1.5 to 20% by weight in the recording liquid composition
15% by weight is contained. If it is less than 1% by weight, the concentration is too low, which is not preferable as a recording liquid. If it is used in an amount of 20% by weight or more, the dispersibility of the pigment deteriorates, the thixotropy is developed, and ink ejection is hindered.

The resin used in the ink jet recording liquid of the present invention is dissolved in the recording liquid and is present. The resin improves the dispersibility of the pigment and improves the fixability of the printed ink on the recording paper. Works to prevent the spread of ink. Such resins include butyral resins such as polyvinyl butyral, acrylic resins such as water-soluble acrylic resins, alkylene glycol resins such as polyethylene glycol, rosin resins, vinyl alcohol resins such as polyethylene glycol, and polyvinylpyrrolidone resins. It is. Particularly, a butyral resin, a water-soluble acrylic resin, polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene glycol are preferable. When a butyral resin is used, the molecular weight is 2,000 to 1
From the viewpoint of dispersion stability, it is desirable to use those having a molecular weight of 00,000, preferably 3,000 to 10,000. When water is added to the recording liquid, it is desirable to use a water-soluble resin as the resin. These resins are used in the ink composition in an amount of 0.01 to 10% by weight, preferably 0.0 to 10% by weight.
It is used in an amount of 5 to 8% by weight, more preferably 0.1 to 7% by weight. When the amount is less than 0.01% by weight, the dispersion stability of the pigment is deteriorated, and when the amount is more than 10% by weight, the viscosity of the ink becomes too high. Become.

The additives used in the ink jet recording liquid of the present invention include alginate and borneol.
At least one kind selected from the group is used. These additives dissolve and exist in the recording liquid, improve the dispersibility of the recording liquid, and particularly effectively work to prevent the bleeding of the ink onto the recording paper and the show-through. As alginate, for example, metal alginate, ammonium alginate and the like, and as borneols, for example, borneol, isoborneol and the like can be used.

These additives are used in the recording liquid composition in an amount of 0.0
It is added in an amount of 0.01 to 5% by weight, preferably 0.003 to 4.5% by weight, and more preferably 0.05 to 4% by weight. If the amount is less than 0.001% by weight, ink bleeds and show-through becomes noticeable. If it is more than 5% by weight, the viscosity of the recording liquid increases, the fluidity becomes poor, and the dispersibility is also adversely affected.

In the present invention, other additives such as a humectant, an emulsifier, and an anti-drying agent may be appropriately added. Specifically, humectants such as aliphatic alcohol amines (such as triethanolamine), alkylamines (such as triethylamine) and lower aliphatic alcohols (such as ethanol, propanol and hexal), aromatic polyglycol ethers and alkylaryl polyglycol ethers ,
Emulsifiers such as sorbitan monooleate; and drying inhibitors such as alkyl naphthalene sulfonate and alkyl aryl sulfonate. When these additives are used, they are added in an amount of about 0.05 to 5% by weight in the recording liquid composition. If the amount is less than 0.05% by weight, the effect of the addition is not obtained. If the amount is more than 5% by weight, the composition of the recording liquid is liable to change due to the ease of evaporation, resulting in poor storage stability. Will be lacking. The additives are selected so as to be dissolved in the recording liquid.

In the present invention, other additives such as 2,2'-thiodiethanol, formamide, glycerin, ethylene carbonate, and methanesulfonic acid may be used according to the type and type of the ink jet printer. The additives have a function of preventing bleeding, feathering and show-through of a printed image.

The ink jet recording liquid of the present invention is produced by mixing, stirring, and kneading the above-mentioned materials using a stirrer. During the production, if necessary, a resin, a solvent, a dispersant, etc. may be added again, or in an optional step or as a final step, filtration may be performed to remove coarse particles, or in a low vacuum. For defoaming.

As a specific device, a ball mill pot,
Commercially available products such as a paint conditioner, a circulation type ultrasonic homogenizer, a sand mill, an ultrasonic dispersion device, and a roll mill can be used.

However, it is preferable to prepare the recording liquid in a clean and dry atmosphere from the viewpoints of production stability and ink ejection stability. Further, when the above process is performed while maintaining the entire apparatus at a constant temperature, a recording liquid having more excellent dispersion stability can be obtained.

The ink-jet recording liquid finally obtained is adjusted to a viscosity suitable for each ink-jet system. As the inkjet method, continuous ejection type (continuous type), volume change ejection type (piezo type), electrostatic type, bubble jet (thermal inkjet type)
Etc. are known. The viscosity and surface tension can be adjusted by selecting the type, combination, ratio, and the like of the composition.

In the case of a continuous discharge type (continuous type), the viscosity is 2.2 to 20 cp, preferably 2.5 to 10 cp.
cp and the surface tension are adjusted to 15 to 65 dyne / cm, preferably 20 to 60 dyne / cm. 20cp viscosity
If it is higher, the recording liquid will not easily come out of the nozzle, and if the surface tension is lower than 15 dyne / cm, liquid dripping will occur.

In the case of the volume change discharge method, the viscosity is 2.2 to 3
0 cp, preferably 2.5 to 20 cp with a surface tension of 20 to 20 cp.
60 dyne / cm, preferably 25-60 dyne /
Adjust to cm. If it is higher than 30 cp, the recording liquid cannot be sufficiently supplied, and if it is lower than 20 dyne / cm, liquid dripping occurs.

In the case of the electrostatic type, the viscosity is 2.2 to 40 cp, preferably 2.5 to 30 cp, and the surface tension is 15 to 60 dy.
ne / cm, preferably 20 to 55 dyne / cm. When the viscosity is higher than 40 cp, it is difficult for the liquid to come out of the slit nozzle, and when the viscosity is lower than 15 dyne / cm, liquid dripping occurs.

In the case of the bubble jet type, the viscosity is 2.2.
-30, preferably 2.5-20 cp, with a surface tension of 15
６５65, preferably 20 to 60 dyne / cm.

When the viscosity is higher than 30 cp, the recording liquid cannot be supplied sufficiently, and it becomes difficult for the recording liquid to come out of the nozzle. When the surface tension is lower than 15 dyne / cm, liquid dripping occurs.

In the case of the thermal / electrostatic method described in Japanese Patent Application No. 3-296797, the viscosity is 4 to 200, preferably 4 to 1.
Surface tension 25-55, preferably 25-5
Adjust to 0 dyne / cm. If the viscosity is higher than 200 cp, it becomes difficult to eject ink.

The lower limit of the viscosity and the upper limit of the surface tension of each of the recording liquids are limited by the composition.

[0044]

Examples (Examples of ink production) The solvents, pigments, dyes, dispersants, and additives shown in Tables 1 to 3 below were used. In Examples 1 to 4 , paint conditioners (manufactured by Red Devil Co., Ltd.) were used. ) For 4 hours, Example
Samples 5 to 7 were treated with a circulation ultrasonic homogenizer (manufactured by Nippon Seiki) for 2 hours, and Comparative Examples 1 to 5 were treated with a paint conditioner (manufactured by Red Devil) for 4 hours.

In the tables, the numbers shown in brackets [] indicate the weight% with respect to the recording liquid.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

(Evaluation of Ink) For the ink obtained as described above, the viscosity, dispersibility, bleeding, show-through, fixability, light resistance, density, water resistance,
The translucency was evaluated as follows, and the results are summarized in Table 4 .

(Viscosity): Precision viscometer (model: Low shear 3)
0, manufactured by Contraves). At that time, the temperature was set at 25 ° C. in a constant environment.

Further, the change in viscosity when a shear (shear stress) was applied was measured, and the dependency of the viscosity on the shear rate was evaluated. For example, when there is a relationship between the viscosity and the shear rate as shown in FIG. 1 (a), the shear rate dependency indicates that the dispersibility is good, and the relationship as shown in FIG. 1 (b). Some cases indicate poor dispersibility.

(Surface tension): Surface tensiometer (model: CBV)
P-A3, manufactured by Interface Science Co., Ltd.). At that time, the temperature was set at 25 ° C. in a constant environment.

(Dispersibility): Dispersibility was evaluated by measuring viscosity and shear rate dependency as described above. That is, thermal shock (−20 ° C.)
(A heat cycle of 90 ° C. was performed 4 times / day, and each temperature was kept for 1 hour), and changes in the graph before and after that were examined. The evaluation was ranked as follows.

：: No change before and after the test, indicating good dispersion stability.

X: There is a change before and after the test, and separation and aggregation occur when stored for a long time.

(Bleeding): Evaluation was performed using a Minolta original evaluation machine using a commercially available XY plotter (with a program function) and a plotter pen. That is, a plotter pen tip (inner diameter 0.1, 0.2, 0.3, 0.5 m
m) and a microdispenser, draw a line with a plotter in a non-contact state with the paper while quantitatively supplying ink to the pen tip, and measure the spread (bleed) with respect to the inner diameter width,
Ranking was performed as follows. The paper used at this time is plain paper EP paper for Minolta camera copiers.

◎: Spreading rate: 0 to less than 10% ：: Spreading rate: less than 10 to 20% Δ: Spreading rate: less than 20 to 30% ×: Spreading rate: 30% or more (Offset): Bleeding was measured. In the same manner as above, the pen inner diameter was fixed at 0.5 mm, a solid pattern of 5 mm square was drawn on paper, and the value obtained by subtracting the reflection density of the paper only from the reflection density measurement value on the back surface was measured. Was ranked.
However, the reflection density was measured using a Sakura densitometer PDA-65 (manufactured by Konishi Roku Photo Industry Co., Ltd.).

◎: Less than 0.1 ０．１: 0.1 to less than 0.2 Δ: 0.2 to less than 0.3 ×: 0.3 or more Desirably rank “○” or more.

(Fixing speed): A solid pattern was drawn as in the case of the show-through evaluation. Immediately after that, a polyurethane blade (a cleaning blade of a copying machine manufactured by Minolta) was scanned with no load like a wiper to remove ink wiping stains. The time until disappearance was measured and ranked as follows.

◎: less than 2.5 seconds ：: less than 2.5 to 5 seconds Δ: less than 5 to 10 seconds ×: 10 seconds or more Rank “○” or more is desirable.

(Light fastness): A solid pattern was drawn in the same manner as in the show-through evaluation, and the initial reflection density (I ₀ ) was measured. Thereafter, exposure was performed for 200 hours under a fluorescent light of 5000 lux to deteriorate the light, and the reflection density (I ₁ ) was measured again. I ₁ / I
The ratio of ₀ (%) was calculated and evaluated as follows.

◎: 100 to 98% or more ：: Less than 98% to 96% or more Δ: Less than 96% to 94% or more X: Less than 94% Rank “○” or more is desirable.

(Density): A solid pattern was drawn in the same manner as in the show-through evaluation, and the image density was measured with a reflection densitometer (Sakura Densitometer PDA-65, manufactured by Konica), and evaluated as follows.

◎: 1.2 or more ○: less than 1.2 to 1.0 Δ: less than 1.0 Rank “○” or more is preferable.

(Water resistance): A solid pattern was drawn in the same manner as in the show-through evaluation, and immersed in pure water for 10 minutes. Thereafter, it was dried and the image density was measured. The decrease from the initial value was calculated and evaluated as follows.

◎: less than 0.1 ：: 0.1 or more to less than 0.2 Δ: 0.2 or more to less than 0.3 ×: 0.3 or more The rank “」 ”or more is preferable.

(Transparency): Coat OHP paper (OHP film I)
N-0030: A solid image is printed on a 5 mm2 area on a Sharp Densitometer (Sakura DENSITO).
The transmission density was measured by METER PDM5 (TRANSMISSION mode). In consideration of this value and the visual evaluation when actually projected by an OHP machine, evaluation was made as follows.

◎: Fine color development ：: Fine color development but slightly dull.

Δ: The color turns black, but can be determined.

×: The color does not come out and becomes black.

[0071]

[Table 4]

[0072]

[0073]

The ink jet recording liquid of the present invention is excellent in translucency and dispersibility, and does not bleed into a printed image or show off.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the relationship between viscosity and shear rate.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-92368 (JP, A) JP-A-63-210181 (JP, A) JP-A-54-62005 (JP, A) JP-A-4- 132774 (JP, A) JP-A-5-247391 (JP, A) JP-A-63-137976 (JP, A) JP-A-5-295310 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) C09D 11/00-11/20

Claims (3)

(57) [Claims] 1. A dispersion medium comprising a non-aqueous solvent having a boiling point of 150 ° C. or higher, 0.5 to 10% by weight of a pigment, and 0.5 to 10% by weight.
An ink jet comprising: by weight of a dye, 0.01 to 10% by weight of a resin soluble in the dispersion medium, and 0.001 to 5% by weight of borneols. Recording liquid. 2. A non-aqueous solvent having a boiling point of 150 ° C. or higher.
A dispersion medium, 0.5 to 10% by weight of a pigment,
% By weight of the dye and 0.01 to 10% by weight of the dispersion medium.
Soluble resin, 0.001 to 5% by weight of alginate
Characterized by containing water and not containing water
Recording liquid. 3. A non-aqueous solvent having a boiling point of 150 ° C. or higher.
A dispersion medium, 0.5 to 10% by weight of a pigment,
% By weight of the dye and 0.01 to 10% by weight of the dispersion medium.
Soluble resin and 0.001 to 5% by weight of alginate
And 7 to 50% by weight of water.
Recording liquid for inkjet.