JP2003073594A - Ink-jet recording composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for ink-jet recording that can achieve high- accurate and stable recording on the target substance with high stability as a jetting composition and high clogging resistance and can increase expression resolution by minimizing the dot sizes. SOLUTION: The ink-jet recording composition comprises fine particles of cellulose that has the average polymerization degree (DP) of <=100, the fraction of the cellulose I type crystal component is <=0.1, the fraction of the cellulose II type crystal component is <=0.4 and the average size of the cellulose particles of <=2 μm, a liquid dispersant and a functional compound and has the maximum ηmax is represented by ηmax =1×10<3> mPa.s, measured with prescribed procedures.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to inkjet ejection, which can be applied to technical fields other than printing where inkjet recording is effective, such as inkjet printing, manufacturing of electronic devices, and biomolecular examination. It relates to a composition.

[0002]

2. Description of the Related Art Inkjet recording technology is
It can realize the formation of precision images, the printing of precision circuits, the fine spotting of functional compounds on the surface of target substances, etc. by an inexpensive and relatively simple method, and its application range has been expanding in recent years. . The ink jet recording method is mainly (1) a method of ejecting a droplet by pressure by electro-mechanical conversion of a piezo element (piezo method), (2) generating a bubble by electro-thermal conversion to press the droplet. There are a method of discharging (thermal method), (3) a method of sucking and discharging liquid droplets by electrostatic force (electrostatic method), and the like. As a technology commonly required for ink jet recording, it is possible to provide an ejection composition that has high stability and safety, does not cause clogging, quickly fixes on the surface after ejection, and has less bleeding due to diffusion. Can be mentioned.

In particular, the recording technology based on the above-mentioned method can inexpensively print cleanly. Therefore, in the field of ink jet printing, the following points are well-balanced as technical problems relating to the ejection composition, that is, the ink composition. Is required (Japanese Patent Laid-Open No. 2001-899).
82). (1) Coloring with sufficient density is possible,
(2) Good storage stability, (3) Excessive bleeding does not occur (ink droplets fixed to a target substance such as paper do not spread excessively, and keeps a certain size to dry), (4) nozzle No clogging, (5) Wide color expression range.

There are pigment-based ink compositions and dye-based ink compositions for ink jet printing. In both of them, the viscosity increases when the concentration of the colorant is increased in order to enhance the color development during printing. However, there is a problem in that the storage stability is lowered at the same time as the increase in the density and the tendency to cause clogging. Further, when an excessive amount of a surfactant or a polymer dispersant is added in order to stabilize the dispersion of fine particles in an aqueous ink containing fine particles such as pigments and resin fine particles, the viscosity of the ink composition also increases, There has been a problem that it also causes bubbles and a decrease in defoaming property.

Generally, JP-A-2001-89982, JP-A-2001-55531, and JP-A-2001-98194.
As described in JP-A No. 2003-242, it is common sense to make the viscosity of ink as low as possible to improve the storage stability of ink and the prevention of clogging during ink jet recording. Specifically, in JP 2001-55531 A, the viscosity at 25 ° C. is 25 mPa · s or less, and in JP 2001-98194 A, the viscosity at 25 ° C. is 1 or less.
It is set to 5 cP (= 15 mPa · s) or less. However, in these viscosity ranges, there is a problem that the addition amount of the colorant or the like for improving the color developability is limited.

In other words, the current situation is that none of the current ink jet recordings satisfy the above technical problems (1) to (4) at the same time. By the way, not only in ink jet printing, but also in the field of applying ink jet recording by using a composition for ink jet ejection to which a functional compound other than a colorant is added, improvement in image resolution in recent years, device integration Due to needs such as improvement of density and inspection efficiency, miniaturization of the size (dot size) after fixing and drying of recording droplets in inkjet recording, that is, improvement of expression resolution is one of common technical problems. .

[0007]

That is, according to the present invention, a functional material having a sufficient concentration can be immobilized on the surface of a target substance, the storage stability is high, and recording on the target substance with high precision and high resolution is possible. It is an object of the present invention to provide an inkjet discharging composition which can be performed in a wide range of fields including printing, without causing clogging during recording.

[0008]

DISCLOSURE OF THE INVENTION The inventor of the present invention has disclosed that
No. 1-181539, PCT / JP98 / 05
The ink composition for inkjet utilizing the dispersion stabilizing ability of the transparent to translucent cellulose dispersions disclosed in 462 in a wide range of compounds does not cause agglomeration of blending components at all, and is similar to the thermal system. As a result of paying attention to the fact that it exhibits excellent ink properties such as being extremely stable because the temperature change of the rheological properties is small in a printing method with a wide temperature gradient, it has been considered difficult only by using the cellulose dispersion to achieve high The present invention has been completed by finding that it is possible to simultaneously satisfy the above-mentioned technical problems even in the viscosity range, and that a substance exhibiting a gel-like property is particularly excellent even in the above-mentioned high viscosity range.

That is, according to the present invention, 1. The average degree of polymerization (DP) is 100 or less, and the cellulose I
Cellulose fine particles in which the fraction of the type II crystal component is 0.1 or less, the fraction of the type II cellulose crystal component is 0.4 or less, and the average particle size of the cellulose particles is 2 μm or less, a liquid dispersion medium, and a function. At least 1 × at 25 ° C., which is measured by using a cone-and-plate type rotational viscometer of the composition.
The maximum value of viscosity (η in the viscosity-shear stress curve obtained in the shear rate region including 10 ⁻³ s ⁻¹ to 1 × 10 ² s ⁻¹⁾
_max ) is η _max ≧ 1 × 10 ³ mPa · s. The maximum value (η _max ) of viscosity described in 2 and 1 is η _max ≧ 5 ×
The composition for inkjet discharge according to 1, wherein the composition is 10 ⁵ mPa · s. 3, the functional compound is a colorant 1
Alternatively, it relates to the composition for inkjet discharge described in 2.

The present invention will be described in detail below. The present invention relates to an inkjet discharging composition for inkjet discharging, which can be widely applied in an application technical field of inkjet recording including inkjet printing, electronic device production, and biomolecular examination, and in particular, The present invention relates to an aqueous inkjet discharging composition for inkjet recording, which contains cellulose as a viscosity modifier.

The cellulose used as the viscosity modifier of the ink jet ejection composition of the present invention has an average degree of polymerization (DP) of 100 or less, a cellulose I type crystal component fraction of 0.1 or less, and a cellulose II type crystal component. If the fraction is 0.4 or less,
The average particle diameter is 2 μm or less, and each structural factor will be described below. The average degree of polymerization of cellulose used in the present invention, the fraction of the cellulose type I crystal component, the fraction of the cellulose type II crystal component, and the average particle size are measured with respect to the cellulose / water dispersion used as a raw material or a dried product thereof. Is.

The average degree of polymerization (DP) of cellulose is preferably 10 or more and 100 or less, and more preferably 20 or more and 50 or less. When the DP is larger than 100, it is difficult to obtain a finely and highly dispersed cellulose dispersion in a dispersion medium, and the thickening property and dispersion stability of the inkjet discharging composition of the present invention are poor. Further, in DP of 10 or less, the water-soluble component is actually contained at a certain content rate,
Again, this is not suitable because it substantially reduces the cellulose fraction that functions as a viscosity modifier.

The fraction (χ _I ) of the cellulose type I crystal component contained in the solid of the cellulose fine particles is 0.1 or less, preferably 0, and the fraction of the cellulose type II crystal component (χ
_II ) is required to have a low crystallinity of 0.4 or less, preferably 0.3 or less. The fraction of the crystalline component of the cellulose of the present invention (χ _c , that is, the sum of χ _I and χ _II ) can be brought to a value close to zero. χ _I exceeds 0.1 or χ
A composition containing cellulose having _II of more than 0.4 has low transparency and low viscosity, and therefore is not suitable as the inkjet discharging composition of the present invention.

The average particle diameter of cellulose is 2 μm or less,
It is preferably 1 μm or less, more preferably 0.5 μm or less. The lower limit of the average particle diameter can be set to about 0.02 μm, which is close to the lower limit of detection in the measuring method specified by the present invention. When it exceeds 2 μm, the thixotropy, which is a characteristic of the inkjet discharging composition of the present invention, is lowered, and at the same time, the nozzle is easily clogged, which is not suitable.
The average degree of polymerization (DP) of cellulose, the fractions of cellulose I and cellulose II type crystal components (χ _I and χ _II ), and the average particle diameter are as described above when the composition for inkjet discharge of the present invention is produced. The cellulose dispersion used (mainly an aqueous dispersion) or a dried product thereof is measured by the following procedure.

As for DP, the intrinsic viscosity [η] was measured by measuring the specific viscosity of a dilute cellulose solution obtained by dissolving a dried cellulose sample obtained by drying a cellulose dispersion in cadoxene with an Ubbelohde viscometer (25 ° C.). From the following viscosity formula (1)
And calculated by the conversion formula (2). [η] = 3.85 × 10 ^-2 × M _w ^0.76 (1) DP = M _w / 162 (2) The fraction (χ _I ) of the cellulose I-type crystal component was also obtained by drying the cellulose dispersion raw material. The obtained dry cellulose sample was pulverized into powder and molded into a tablet, which was obtained by a radiation source CuKα and a wide-angle X-ray diffraction method using a reflection method (using Rotaflex RU-300 manufactured by Rigaku Denki Co., Ltd.). In the diffractogram (FIG. 1), from the absolute peak intensity h _{0 at} 2θ = 15.0 °, which is assigned to the (110) plane peak of the cellulose type I crystal, and the peak intensity h ₁ from the baseline at this plane interval, The value obtained by the following equation (3) was used.

Similarly, the fraction (χ _II ) of the cellulose II type crystal component is assigned to the (110) plane peak of the cellulose II type crystal in the obtained diffractogram (FIG. 1) by 2θ.
From the absolute peak intensity h ₀ * at = 12.6 ° and the peak intensity h ₁ * from the baseline at this plane interval,
The value obtained by the following equation (4) was used. χ _I = h ₁ / h ₀ (3) χ _II = h ₁ * / h ₀ * (4) Incidentally, FIG. 1 shows a schematic diagram for obtaining χ _I and χ _II .

The average particle size of cellulose is measured by a laser diffraction type particle size distribution measuring device (manufactured by Horiba, Ltd., laser diffraction / scattering type particle size measuring device) for a dispersion prepared by dispersing the raw material cellulose in a liquid dispersion medium. LA-920; lower limit detection value is 0.02 μm) and is a weight (volume) average particle diameter obtained by measurement at room temperature. In order to measure the particle size in a state where the association between particles in the dispersion medium is cut as much as possible,
The sample was prepared in the next step. Cellulose concentration is about 0.5
After diluting the cellulose dispersion raw material with water so as to have a weight percentage, the mixture is mixed for 10 minutes with a blender having a rotation speed of 15,000 rpm or more to prepare a uniform highly transparent dispersion liquid.

Next, this dispersion liquid sample was supplied to a flow cell of a particle size distribution measuring apparatus, and after ultrasonic treatment was appropriately performed,
The particle size distribution was measured. The range of the concentration of cellulose contained in the inkjet discharging composition of the present invention is 0.1
˜5.0 wt%, preferably 0.3 to 4.0 wt%, more preferably 0.5 to 2.5 wt%. When the cellulose concentration is lower than 0.1% by weight, various effects claimed in the present invention cannot be expected.
Further, when the concentration of cellulose exceeds 5.0% by weight, the viscosity of the gelled substance becomes extremely high, so that air easily enters the composition for inkjet ejection in the storage chamber of the inkjet recording device, and the liquid transfer to the nozzle itself occurs. Not suitable because it will be difficult.

Next, the liquid dispersion medium used in the ink jet composition of the present invention will be described. The liquid dispersion medium of the present invention is usually water, but water-soluble organic solvents such as alcohols may be used in addition to water. It is also possible to use a hydrophobic organic solvent depending on the purpose. These may be used as a mixed medium. Examples of the water-soluble organic solvent include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-
Alkyl alcohols having 1 to 4 carbon atoms such as butyl alcohol, dimethylformamide, dimethylacetamide,
Ketones or keto alcohols such as acetone and diacetone alcohol, ethers such as tetrahydrofuran and dioxane, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexanetriol, thiodiglycol,
Alkylene glycols having an alkylene group of 2 to 6 carbon atoms such as hexylene glycol and diethylene glycol, cellosolves such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene Glycol mono-n-butyl ether, diethylene glycol-n-
Carbitols such as butyl ether and triethylene glycol-n-butyl ether, 1,2-hexanediol,
1,2-Alkyldiols such as 1,2-octanediol, polyethylene glycol, polypropylene glycol, glycerin and its derivatives, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidi You can list non,
It is not limited to these.

Examples of the hydrophobic organic solvent include hydrocarbons such as hexane and toluene, and esters such as ethyl acetate. The liquid dispersion medium is appropriately selected according to the purpose of inkjet recording and the type of target substance (plain paper, various special papers, various film sheets, various glasses, etc.) for recording (printing, etc.). The composition range of the liquid dispersion medium in the composition for inkjet discharge of the present invention is, as the total weight% of the liquid dispersion medium contained in the composition for inkjet discharge,
50% by weight to 98% by weight, preferably 60% by weight to 95%
It is in the range of% by weight. If it is less than 50% by weight, clogging frequently occurs, and stable ejection of droplets from the nozzle cannot be expected. On the other hand, when it exceeds 98% by weight, it becomes difficult to prepare the composition for inkjet discharge in the viscosity range defined in the present invention, which is also unsuitable.

The composition for ink jet ejection of the present invention is
In addition to cellulose and a liquid dispersion medium, it is characterized by containing a functional compound depending on the purpose of ink jet recording. The functional compound is, for example, a coloring agent such as a dye or a pigment when the purpose is an ink for printing, as described later. In addition, when the purpose of ink jet recording is an interlayer insulating layer in semiconductor circuit manufacturing, silica fine particles or low-dielectric polymer fine particles that can serve as a base material having an insulating property, or DNA when the composition is a spotting composition for a probe array. In the case of medical diagnostic devices, there are various substances such as antibody substances and adsorptive compounds against detection target substances.

In selecting a functional compound, it is important to freely select it within a range satisfying the following two conditions. First, the functional compound is dissolved or highly dispersed in a selected liquid dispersion medium. Here, in order to highly disperse, it is necessary that the average particle diameter of the functional compound (particles) does not exceed about 10 μm, preferably does not exceed 5 μm. Next, the functional compound should not accelerate the aggregation of cellulose in the inkjet discharging composition. As a substance that promotes the aggregation of cellulose,
An electrolyte (ionic substance) that can be dissolved in a liquid dispersion medium can be used, but when it is desired to mix these, a small amount is added so that the cellulose does not aggregate.

All of the conditions are necessary for imparting the anti-clogging property claimed in the present invention as an ink jet discharging composition. Although it varies greatly depending on the purpose, the composition range of the functional compound in the inkjet discharging composition of the present invention is about 0.01% by weight as a total weight% of the functional compounds contained in the inkjet discharging composition. 40% by weight, preferably 0.1% to 30% by weight
Is the range. Below 0.01% by weight, in many cases
Even if the liquid dispersion medium dries after recording, the intended function cannot be expected because the concentration is too low. On the other hand, if it exceeds 40% by weight, it is difficult to suppress the occurrence of clogging and to secure the stability of the composition for inkjet discharge, which is unsuitable.

Further, the composition for inkjet discharge of the present invention
Items are measured using a cone and plate type rotational viscometer.
At least 1 x 10 at 25 ° C^-3s^-1-1 x 10
²s^-1Viscosity obtained in the shear rate region including
Maximum value of viscosity on the curve (η _max) Is η_max≧ 1 × 1
0³It is necessary to be mPa · s. Figure 2 and Figure
Η specific to 3_maxCellulose of the present invention as a measurement example of
Composition for ink jet containing 2.0% by weight of
Of one example (sample S3 in Example 3) at 25 ° C.
Viscosity (η) -shear rate (γ '= gamma dot) curve
Line and viscosity (η) -shear stress (τ) curves are shown respectively.
did.

The cone and plate type rotational viscometer is Haa
Using a ke rheometer, RS-100, 4 °,
This was done using a cone with a diameter of 35 mm. In FIG.
When τ is about 3 Pa or less, η shows a so-called Newtonian viscosity, which is almost constant without depending on τ, but τ is 3 Pa.
When it exceeds, the viscosity is drastically reduced, and for example, at τ = 30 Pa, the viscosity shows an extremely low value of about 100 mPa · s. This is due to the high thixotropic property of the raw material dispersion of the composition for inkjet discharge constituting the present invention, but at the same time, compared with the same curve of other materials, the critical shear stress at which τ starts to rapidly decrease ( When the value of τ _c ) in FIG. 3 is extremely small, the composition for inkjet ejection has an extremely high viscosity in the storage chamber, but has a low viscosity due to low stress, and there is no clogging of the nozzle from the storage chamber of the inkjet recording apparatus. It can be said that liquid transfer is possible.

Further, since the liquid droplets ejected from the nozzle try to return to the original highly viscous state immediately after being ejected due to the thixotropic property, most of the viscosity is recovered at the time of reaching (landing) on the surface of the target substance. , The area of the landing droplet does not spread too much on the landing surface, and the landing surface is fixed with an appropriate size. Due to this property, it is possible to record while controlling minute dots, and it is possible to increase the resolution of the image as compared with the conventional case. In the case of a low-viscosity inkjet discharging composition having a value of η _max of less than 1 × 10 ³ mPa · s, the effect of suppressing aggregation of other dispersed components claimed in the present invention is reduced and, at the same time, spread of droplets at the time of landing. You can no longer expect the effect of suppressing. If η _max ≧ 1 × 10 ³ mPa · s, and more preferably 1 × 10 ⁴ mPa · s or more, the effect claimed in the present invention can be sufficiently expected.

However, when η _max is in the range of 1 × 10 ³ mPa · s or more and less than 5 × 10 ⁵ mPa · s, the composition of the ink jet ejection composition is a fluid and highly viscous liquid composition. The value of η _max is 5 in order to further suppress the spread of droplets at the time of landing and reduce the dot area to achieve high resolution.
× 10 ⁵ mPa · s or more, more preferably 5 × 10 ⁶ m
Pa · s is recommended. Η of 5 × 10 ⁵ mPa · s
The value of _max is the viscosity at which the composition becomes gel-like. Such adjustment of viscosity is properly used according to the purpose of ink jet recording. It is desirable that the value of η _max does not exceed 10 ⁹ mPa · s as a range in which liquid can be transferred stably from the storage chamber to the nozzle without clogging. The pH range of the inkjet ejection composition of the present invention is 3 to 1.
0, the more preferred pH range is 3.5-9. This is because if the pH is less than 3 or more than 10, strong aggregation of the cellulose constituting the composition occurs and clogging near the nozzle is likely to occur.

By the way, various additives can be added to the composition for ink-jet ejection of the present invention depending on the purpose. In particular, when a water-soluble polymer is added for the purpose of stabilizing dispersion, etc. Be careful. That is, a solution of a high-molecular-weight water-soluble polymer has a high spinnability, but this property significantly hinders the work of cutting the liquid droplet at the nozzle outlet during the ejection of inkjet recording. That is, it is important to add and mix the composition for inkjet discharge in a range where the composition does not have spinnability.

In order to satisfy this condition, for example, when a relatively large amount of a water-soluble polymer is added for the purpose of stabilizing the pigment dispersion, it is necessary to consider that the molecular weight is low. . When the average molecular weight is 100,000 or more, the water-soluble polymer to be added to the inkjet discharging composition of the present invention is 2% by weight or less, preferably 1% by weight or less, and the average molecular weight is several%. In the case of a polymer having a relatively low molecular weight of about 1,000 to tens of thousands, 5% by weight or less, preferably 3% by weight, relative to the total amount of the composition for inkjet ejection.
The following is good. In order to improve the stability of the composition for inkjet ejection, it is also very effective to add a small amount of a polyhydric alcohol such as glycerin or ethylene glycol.

Next, a method for preparing the ink jet discharging composition of the present invention will be described. The composition of the present invention is PCT / JP9
8/05462, a cellulose dispersion provided by
In particular, it is most desirable to produce the cellulose / water dispersion as a raw material. First, a method for producing a cellulose dispersion will be described. A natural or regenerated cellulose raw material is dissolved in an inorganic acid aqueous solution such as sulfuric acid, the solution is reprecipitated with a precipitant such as water, hydrolyzed, and washed / concentrated to obtain an aqueous dispersion. If necessary, after substituting with an organic solvent such as ethanol, it can be further subjected to micronization treatment with a mixer.

The dispersion medium in the cellulose dispersion thus obtained is usually water as described above, but depending on the purpose, methanol, ethanol, isopropanol, acetone, acetonitrile, dimethylsulfoxide, dimethylformamide are used. It may be partially or wholly replaced with a water-soluble organic solvent such as dimethylacetamide or a mixed solvent thereof.

On the other hand, in a special case such as the case where the intended composition for ink jet ejection uses a non-aqueous dispersion medium having extremely strong hydrophobicity, hydrocarbons such as hexane and toluene which are hydrophobic organic solvents, It is necessary to use cellulose as an ester such as ethyl acetate, and in this case, after replacing with a water-soluble organic medium at the stage of removing the inorganic acid in the above-mentioned preparation step, further using a hydrophobic organic solvent. Replace. The dispersion used as a raw material in the present invention is preferably obtained by further pulverizing the dispersion obtained by dispersing the cellulose obtained as described above with a high pressure / ultra high pressure homogenizer or the like. By using the dispersion that has been subjected to this treatment as a raw material, it is possible to obtain the composition for inkjet discharge of the present invention, which is more excellent in quality stability. The advanced crushing treatment may be performed multiple times.

The ink jet composition of the present invention comprises:
A dispersion of the cellulose fine particles obtained as described above is mixed with one or more functional compounds selected according to the purpose and other additives, and a liquid dispersion medium such as water or a water-soluble organic solvent. Then, dispersion treatment is performed to prepare the composition for inkjet ejection of the present invention. For example, in the case of producing the inkjet discharging composition of the present invention as an ink composition, a colorant such as a pigment or a dye is used as a functional compound, and various additives described below and a water-soluble organic solvent are added. In addition, in the present invention, an inkjet ejection composition using a colorant as a functional compound is particularly referred to as an ink composition.

The dispersion treatment here means various mixers such as a low-speed kneader, a vacuum homomixer, a disper, a propeller mixer, and a kneader, various grinders, blenders, homogenizers, ultrasonic emulsifiers, colloid mills, pebble mills, ball mills, It means a dispersion treatment using a sand mill, a line mill, a planetary ball mill, a bead mill grinder, a high pressure homogenizer, an ultrahigh pressure type homogenizer, or the like. It is effective to carry out a filtering operation with a filter or the like in order to remove aggregates in the composition for inkjet discharge after the dispersion treatment, since the anti-clogging property can be further enhanced. These treatments may be selected according to the purpose of ink jet recording and the content of the blending components of the composition for ink jet ejection.

The composition for inkjet discharge of the present invention can be prepared as described above. In the inkjet discharging composition of the present invention, the high dispersion stability of the cellulose used in the present invention makes it difficult for the constituent components such as the functional compound to agglomerate, and has a very low probability of clogging despite being highly viscous. It is considered that this is also due to the water retention capacity of the network structure of cellulose formed in the inkjet discharging composition.

Further, since the composition for jetting ink jet of the present invention has an extremely high thixotropy property, at the same time, it has a property of lowering the viscosity by an extremely weak stress.
The composition for inkjet ejection is in a gel state or a highly viscous state in the storage chamber, and becomes a highly fluid liquid state according to the suction force or the pushing force applied in the flow path from the storage chamber to the nozzle. Further, when the liquid droplets are ejected from the nozzle, since there is almost no spinnability, they can be easily cut and ideal liquid droplets can be produced. Since the ejected droplet tries to return to the original highly viscous state immediately after being ejected, most of the viscosity is recovered when it reaches the surface of the target substance (landing), and the area of the landing droplet on the landing surface is restored. Will not spread too much and will be fixed in an appropriate size. And since the droplets contain cellulose with amphipathic properties, the droplets also have a high affinity for a wide range of surfaces, that is, they also have extremely high adhesion to the target surface, depending on the medium composition. good.

Further, the composition for ink jet ejection of the present invention is excellent in temperature stability without lowering the viscosity even at a high temperature of 50 ° C. or higher. This property is convenient, for example, when performing thermal type ink jet recording. As a result of these, the composition for inkjet ejection provided by the present invention has excellent stability when used as an ink, is unlikely to cause clogging, and has no bleeding even after fixing, and can form fine dots. Therefore, high-resolution recording can be performed for a wide range of target substances.

The composition for ink jet ejection of the present invention is
In particular, it is possible to provide an ink composition suitable for inkjet ejection when a colorant is blended as a functional compound. The case where a colorant is used as the functional compound will be described in more detail below. As the colorant, a water-soluble dye, pigments including carbon black or an organic pigment, fine particles of colored resin, and microcapsules containing the colorant are used. Surface-modified carbon black or an organic pigment may be used. The compound is not limited to these as long as it has a coloring effect. Even if these are 1 type, 2
You may mix | blend a seed or more.

The water-soluble dye refers to a disperse dye, a reactive dye, an acid dye, a direct dye, a cationic dye, a mordant dye, a sulfur dye, an azoic dye, and the like, more specifically,
C. I. Various Disperse Yellow, C.I.
I. Various Disperse Orange, C.I. I. D
various types of isperse Red, C.I. I. Dispers
eViolet variety, C.I. I. Disperse Gr
various een, C.I. I. Various Disperse browns, C.I. I. Various Disperse Blue, C.I.
I. Various Disperse Black, C.I. I. Re
various active yellow, C.I. I. React
IVE Orange variety, C.I. I. Reactive
Red, C.I. I. Reactive Video
t various, C.I. I. Various Reactive Blue,
C. I. Various types of Reactive Green, C.I. I.
Reactive Brown, C.I. I. Reac
various types of liveBlack, C.I. I. Acid Yell
ow, C.I. I. Acid Orange, C.I.
I. Various Acid Red, C.I. I. Acid Vio
various let, C.I. I. Acid Blue, C.I.
I. Acid Green, C.I. I. Acid B
various types of C.I. I. Various types of Acid Black,
C. I. Direct Yellow, C.I. I. D
various direct orange, C.I. I. Direct
Red, C.I. I. Various Direct Violet, C.I. I. Various types of Direct Blue, C.I. I. D
various types of direct green, C.I. I. Direct
Various Brown, C.I. I. Examples of DirectBlack include various types, but the present invention is not limited thereto.

Carbon black refers to furnace black, lamp black, acetylene black, channel black and the like, and more specifically, various Raven types,
Various Raven ULTRA series (above, made by Colombian Carbon Co., Ltd.), various Regal, Monarch
Various (above, made by Cabot), Color Blac
k, various Printex, Special Bla
Examples thereof include, but are not limited to, various types of ck (all manufactured by Degussa). When a black pigment is used, the surface of carbon black is modified to -C.
Even if a self-dispersion type carbon black into which a hydrophilic substituent such as an OOX group or a —SO ₃ X group (X represents a hydrogen atom, an alkali metal, ammonium or an organic ammonium) is introduced is used, a suitable ink composition can be obtained. Can be provided.

Specific examples of organic pigments include C.I. I. Pi
gment Yellow various types, C.I. I. Pigmen
t Orange variety, C.I. I. Pigment Re
d various, C.I. I. Pigment Violet,
C. I. Pigment Blue, C.I. I. Pi
gment Green various, C.I. I. Pigment
Various Brown, C.I. I. Pigment Blac
k, etc. can be mentioned, but the invention is not limited to these.

Microcapsules in a form in which a colorant obtained by emulsifying and dispersing from an oil phase containing a resin and a colorant and an aqueous phase are encapsulated in the resin can be used in the same manner as the above colorant. The average particle size of the microcapsules is 0.
01 to 2.0 μm is preferable, and 0.05 is more preferable.
Is in the range of 1.0 μm. A more suitable ink composition can be obtained by using the colorant having the above average particle diameter.
For the microencapsulation of the colorant, in addition to the above, a method of preparing from a monomer while interfacially polymerizing, or a general method of preparing microcapsules such as a coacervation method can be used.

As a method of introducing the resin in the microencapsulation, a method of dissolving the resin in an oil phase in advance and subjecting the resin to phase inversion emulsification, an interfacial polymerization method, a coacervation method, or another ordinary microcapsule preparation method can be applied. The content of these colorants in the ink composition is 0.01 to 40% by weight, preferably 0.1 to 30% by weight, more preferably 0.1 to 20% by weight, and further preferably 0.1. 5-
It is 10% by weight, particularly preferably 1 to 8% by weight. If the blending amount of the coloring material is too large, aggregation of the components in the ink composition is easily promoted, which causes a problem in clogging. If the blending amount is too small, a sufficient degree of color development cannot be obtained as a matter of course.

The ink composition of the present invention comprises a colorant, a liquid dispersion medium such as cellulose, water, a water-soluble organic solvent, and various additives. These can be added as needed, but what is important is that the components of the ink composition of the present invention are not aggregated and the composition is stably maintained in a uniform state. However, the agglomeration referred to here does not correspond to network formation or gentle agglomeration (soft agglomeration) by the cellulose fine particles as an essential component. This is because they are the driving force for various effects of the ink composition of the present invention, and at the same time, they do not cause the clogging of the pipe or the tip of the nozzle.

When the ink composition of the present invention adheres to a target substance such as paper, the ink composition is fixed on the surface of the target substance without expanding the size of the droplet, and the color development is excellent and high resolution printing becomes possible. When the target substance is paper, the cellulose contained in the ink composition also acts as a fixing agent for the target substance. The water-soluble organic solvents listed above can be used, but are not limited thereto. The water-soluble organic solvent improves the ink characteristics in terms of the penetration enhancer of the ink and, in some cases, the immediate drying property.

The liquid dispersion medium contained in the ink composition means a liquid medium such as water or a water-soluble organic solvent, and its content is the total weight% of the liquid dispersion medium contained in the ink composition. , 50% to 98% by weight, preferably 60% to 95% by weight. If it is less than 50% by weight, clogging frequently occurs, and stable ejection of droplets from the nozzle cannot be expected. On the other hand, when it exceeds 98% by weight, it becomes difficult to prepare the ink composition in the viscosity range specified in the present invention, which is also unsuitable.

Particularly when a water-soluble organic solvent is used, 1
Either one kind or two or more kinds may be mixed, but the total content of the water-soluble organic solvent contained in the ink composition is in the range of 5% by weight or more and 60% by weight or less with respect to the total weight of the ink composition. Is preferred. More preferably 10% by weight
The content is preferably 50% by weight or more (for example, when the water-soluble organic solvent is 10% by weight, the other medium such as water is 40% by weight or more, preferably 50% by weight or more from the above description. There is a need).

If it is 5% by weight or less, the effect of mixing the organic solvent is small, and if it exceeds 60% by weight, the cellulose contained in the ink composition often causes strong aggregation and easily causes clogging. And is not desirable because it reduces the rheological properties of the ink composition of the present invention.
Further, the water used in the present invention is preferably ion-exchanged water or pure water. Tap water and ground water are expected to contain chlorine and impurities that affect various ink properties, which is not desirable in terms of ensuring quality.

If desired, various additives may be added to the ink jet composition of the present invention. Examples of the additive include an inorganic salt, a surfactant, an antiseptic, an antifungal agent, a pH adjuster, a dispersion stabilizer, a hydrotope agent, and the like, and the dispersion stability of the ink composition claimed in the present invention and It is important to incorporate these additives to the extent that suitable rheological properties are not impaired. For example, if an inorganic salt or an ionic surfactant is used in a large amount, it has an action of aggregating the cellulose of the present invention, but if it is an appropriate amount, the content of cellulose in the entire composition is, for example, about 0.5% by weight. Even in this case, it is effective because it can impart appropriate thixotropy to the composition for inkjet ejection.

When sodium chloride is used as the inorganic salt, it is, for example, about 0.01% by weight, though it depends on the compounding ingredients.
When added in an amount of 0.1% by weight, it is gelled and highly stable, and exhibits appropriate ink characteristics. However, when added at a single-digit high concentration of 0.1% by weight, it induces strong aggregation of cellulose, resulting in gel and high thixotropic ink characteristics. Are lost. The pH range of the inkjet discharging composition of the present invention is 3 to 9,
A more preferable pH range is 3.5-8. This is because if the pH is less than 3 or more than 9, various components (pigment, dispersion stabilizer, cellulose, etc.) constituting the ink composition are likely to aggregate.

Specific examples of the additives that can be used in the present invention are shown below, but the additives that can be used in the present invention are not limited to these. The addition of the inorganic salt is used for the purpose of improving the stability of the dye. Specific examples thereof include sodium chloride, sodium sulfate, magnesium chloride, magnesium sulfide, etc., but since the inorganic salts have the property of aggregating the cellulose contained in the inkjet discharging composition, the addition amount is It is preferably 0.1 mol / l or less of the total composition for inkjet ejection. Of course, the inorganic salt is not limited to these.

In many cases, the surfactant is used for the purpose of arbitrarily controlling the surface tension of the ink droplets or as a penetration accelerator that enhances the wettability to the recording medium and accelerates the permeability. For this purpose, nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene phenyl ether and betaine amphoteric surfactants are suitable. Of course, it is not limited to these, and two or more kinds of surfactants may be used in combination. Anionic surfactants and cationic surfactants act sensitively on the rheological properties of the ink composition, so it is desirable to add a trace amount of, for example, 0.1 mol / l or less.

In order to maintain the long-term storage stability of the composition for ink jet ejection, an aromatic halogen compound (for example, Pr) is used.
Even preservatives and mildew-proofing agents such as menthol CMK), methylene dithiocyanate, and halogen-containing nitrogen-sulfur compounds may be added. In the case of the ink composition, a pH adjusting agent such as hydrochloric acid, acetic acid, or a dilute aqueous solution of sodium hydroxide or potassium hydroxide may be added in order to keep the dye or pigment stable. A hydrotope agent such as urea or a urea derivative may be added to prevent the ink near the nozzles from drying.

In particular, in order to enhance the dispersibility of the pigment contained in the ink composition, polyacrylic acid, polymethacrylic acid or its ester, salts and their copolymers, polyhydroxyethyl methacrylate and its Water-soluble polymers such as copolymers, polyvinylpyrrolidone, polyvinylpyridinium halides, polyvinyl alcohols of various saponification degrees, carboxy-modified, amphoteric polyvinyl alcohol, polyethylene glycol, polypropylene glycol may be added, but in this case As described above, the addition of an extremely small amount of about 0.2% by weight or less based on the total amount of the composition is added so that the ink composition does not exhibit spinnability.

The composition for ink jet ejection of the present invention is
As described above, it can be suitably used as an ink composition for inkjet printing, but the invention is not limited to this, and the inkjet discharging composition can be provided in all technical fields to which an inkjet recording method can be applied. More specifically, fields of application other than inkjet printing include printing of fine circuit patterns in the manufacturing process of semiconductor devices, and production of probe arrays for the purpose of identifying nucleic acids and bacteria. However, these are merely examples and do not limit the applicable scope.

Among them, the printing of a circuit pattern in a semiconductor device is described in, for example, Japanese Patent Laid-Open No. 2000-3.
The technology is disclosed in No. 3698, but basically,
The idea is to replace what used to be a circuit pattern drawn by laser irradiation using the lithography method until now with inkjet printing. This method has an advantage that a pattern with a higher resolution can be expressed than that drawn by the lithography method, and is expected as a technique that enables the production of a highly integrated semiconductor device. However, in practice, a technology for stacking a circuit made of conductive metal (aluminum or copper) and an insulating layer (silica) separating the device with high accuracy is required. In the composition, the droplets land on the target substrate by printing and simultaneously spread by diffusion, and it is extremely difficult to precisely print the conductive layer and the insulating layer. If applied, it becomes possible to solve such a problem.

That is, the gel-like composition for ink jet ejection of the present invention is prepared as a nano-sized ultrafine particle dispersion such as fumed silica, and a volatile oily compound which is incompatible with water. A low-viscosity inkjet discharging composition (conductive composition) in which conductive fine particles are dispersed is prepared, and the insulating layer composition and the conductive composition are formed according to the circuit pattern set by the inkjet method. Printing on the substrate in order. In some cases, printing the composition for an insulating layer is performed multiple times,
After stacking the insulating layer gel, the printing of the conductive composition is performed a plurality of times.

By the above operation, the conductive dispersion liquid is printed on the groove portion by the insulating layer produced previously, and moreover, the components of both phases are interdiffused by the separation of water / oil. Escape. After the operation, the dispersion medium of both layers is dried and further sintered at a temperature of 400 ° C. or higher. By this operation, the cellulose contained in the insulating layer composition is completely decomposed and removed. However, in the insulating layer composition originally composed of a dispersion medium such as cellulose / silica / water, silica is used in the present invention. It is considered that the components are highly dispersed (Japanese Patent Laid-Open No. 2001-49031).
No.), depending on the conditions, this portion becomes fine pores to form a porous silica layer, and an ideal insulating layer having a low dielectric constant is formed. As a matter of course, the composition for inkjet ejection of the present invention is also effective for producing an insulating layer when the circuits thus drawn are laminated in multiple layers.

This is an example, and although not limited thereto, by effectively utilizing the characteristics of the ejection composition of the present invention, it can be used in a wide range of technical fields in the field of precision processing such as semiconductor device manufacturing. Can be applied. Further, the idea of a probe array for the purpose of identifying nucleic acids and bacteria is, for example, as disclosed in Japanese Patent Laid-Open No. 2001-66305, determination of the base sequence of nucleic acids, detection of target nucleic acids in samples, detection of various bacteria. It has attracted attention as one of the technologies that can perform identification quickly and accurately.

The probe array is, for example, a device for biochemical examination in which a large number of substances (so-called probes) capable of specifically binding to a target nucleic acid are arranged on a solid phase. As one of the production methods, a method of supplying a pre-synthesized nucleic acid probe into a solid phase has been proposed (for example, USP5
405783), for example, when attempting to perform nucleotide sequencing of nucleic acids by this method, in order to efficiently detect mutations in genes, as many nucleic acid probes as possible are arranged (spotted) on a solid phase having a small area. It is desirable to keep.

In Japanese Patent Laid-Open No. 2001-66305, it is described more specifically that it is desirable to spot 10,000 or more nucleic acid probes per square inch. In order to spot such an extremely small amount of a probe on a solid phase efficiently and accurately without damaging the probe, the composition for inkjet ejection of the present invention is used to perform spotting by an inkjet method. Is extremely effective.

That is, according to the technique of the present invention, a material that is chemically inactive, highly stable, and biologically safe, that is, cellulose, is the main component for expressing the viscosity of the composition. As described above, it is suitable for spotting ejection because it enables high-density spotting due to the viscous nature of droplets, and can design a composition with excellent fixability to the target substance. A composition can be provided. For this purpose, in order to protect nucleic acid such as DNA, it is preferable to adopt a piezo method or an electrostatic force method as an inkjet recording method in which the temperature rise of the composition containing the probe can be suppressed. Of course, this is just one application and is not limiting. In addition to this, the composition for inkjet ejection provided by the present invention can be widely applied to a technique for producing a device for a biological test such as a biochip for various purposes and a medical diagnostic purpose.

[0063]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the embodiments of the present invention will be specifically described with reference to the following examples, but these do not limit the scope of the present invention. Prior to the examples, an evaluation method ((1) to (2)) and a production example ((3)) of a cellulose / water dispersion used as a raw material will be described.

(1) Method for Measuring Physical Properties of Cellulose Used in the Present Invention Physical properties of cellulose used in the present invention were measured using a cellulose / water dispersion. The crystal component fractions (χ _I and χ _II ) were obtained by using wide-angle X-ray diffraction (X-ray diffractometer manufactured by Rigaku Denki Co., Ltd. (RU-300 type, Lint system attached)). The pattern was measured by the method described above. The average particle size of the cellulose fine particles is calculated by laser diffraction /
The scattering-type particle size distribution measuring device LA-920 (manufactured by Horiba Ltd.) was used for the measurement. The average degree of polymerization (DP) is determined by measuring the specific viscosity of a dilute cellulose solution prepared by dissolving a dry cellulose sample in a cadoxene solution with an Ubbelohde viscometer (25 ° C.), and using the intrinsic viscosity [η] to calculate the DP Was evaluated. (2) Viscosity (η _max ) of the composition for ink jet ejection The evaluation of η _max was carried out using a cone-plate type rotational viscometer with H
Using RS-100 made by aake, 4 °, 35 mm
The conditions were set so that the shear rate (γ ') included a range of 10 ⁻³ to 10 ² s ⁻¹ at 25 ° C. using a cone plate having a diameter.

(3) Production Example of Cellulose / Aqueous Dispersion A raw material pulp having a degree of polymerization of 760 (hereinafter simply referred to as refined pulp) obtained by cutting the sheet-like refined pulp into 5 mm × 5 mm chips at −5 ° C. A transparent and viscous cellulose dope was obtained by dissolving in a 65 wt% sulfuric acid aqueous solution so that the cellulose concentration became 5 wt%. This cellulose dope was poured into 2.5 times the weight of water (5 ° C.) with stirring to agglomerate the cellulose into flocs to obtain a floc solid dispersion. After hydrolyzing this suspension at 85 ° C. for 20 minutes, the aqueous sulfuric acid solution as the dispersion medium is removed by vacuum filtration using a glass filter, and then the pH of the washing liquid.
After repeatedly washing with water until the pH reaches about 3, then washing (neutralizing) with a dilute aqueous ammonia solution having a pH of about 11, and then further washing with ion-exchanged water to obtain a cellulose concentration of 6.0% by weight. A transparent white gel was obtained.

The obtained gel-like substance was diluted with ion-exchanged water to prepare a cellulose concentration of 4.0% by weight,
1 using a homomixer (TK Lobo.mics ^™ , manufactured by Tokushu Kika Co., Ltd.) at a rotation speed of 15000 rpm.
Dispersion treatment was performed for 0 minutes, and an ultrahigh-pressure homogenizer (Microfluidizer ^™ , M110-E / H type, manufactured by Mizuho Industry Co., Ltd.) was used under a pressure of 1.72 × 10 ⁸ Pa.
Once processed, highly transparent cellulose / water dispersion (pH =
6.7) was obtained. The obtained cellulose / water dispersion is designated as sample A. The wide-angle X-ray pattern of the dried sample A is shown in FIG. When the physical properties of the cellulose contained in Sample A were measured by the above evaluation methods, the average degree of polymerization was 38, the crystallinity was 0 for χ _I , 0.18 for χ _II , and 0.3 μm for the average particle size. there were.

[0067]

Examples 1 to 3 and Comparative Examples 1 to 4 Pigment type ink compositions using carbon black as a functional compound were prepared and their ink characteristics were compared. (1) Examples 1 to 3 (Preparation and Evaluation of Samples S1 to S3) Carbon black S170 as carbon black
^TM (manufactured by Degussa) mixed with 150g of ultrapure water for a total amount of 1K
and crushed by a ball mill using zirconia beads. The obtained dispersion liquid (pigment concentration: 15% by weight) is used as a dispersion liquid B.
And

Using the sample A, the three compositions shown in Table 1
Mix various compounding ingredients so that (Samples S1 to S3)
After that, the homomixer (TK Lobo.mic
s^TM, Manufactured by Tokushu Kika Co., Ltd., at 15000 rpm
Performs dispersion treatment for 10 minutes at rotation speed, and performs vacuum degassing treatment.
Thus, three types of ink compositions were obtained. Cellulose concentration
1.0 wt%, 1.5 wt%, 2.0 wt% ink
Sample S1, sample S2, and sample S3 were used, respectively. Obtained
Η of three other samples at 25 ° C _maxThe values of are shown in Table 1.
Also, for sample S3, cone-plate rotational viscosity
The viscosity (η_max) To evaluate
Specific measurement examples at this time are shown in FIGS. 2 and 3. Obtained
Each commercially available piezo ink jet
Recording device MJ-930^TM(Seiko Epson Corporation)
For black ink cartridges
Fill the boxes with ink samples S1 to S3,
Printing on A4 paper (solid printing and letters "printing"
Was printed). The printing was evaluated by the following method.

Image density (coloring property); printing solid image
After leaving for 12 hours, Macbeth RD-91 reflection densitometer
8 ^TM(Manufactured by Macbeth). Results below
Classified as follows. A: Image density is 1.35 or higher B: Image density is 1.20 to 1.34 C: Image density is less than 1.20 Blurring of printed characters: Visually check if there is blur on printed characters
I judged it. The results were categorized as follows. A: No bleeding is seen B: Some blurring is seen, but letters are clearly recognizable C: Characters are not recognizable due to severe blurring Resolution of printed characters; resolution of printed characters Optical
Observe with a microscope and classify the resolution according to the following criteria.
It was A: Ink / periphery of both the corners and straight lines of the enlarged characters
Can express an extremely sharp image of B: Ink / peripheral image is not visible in the enlarged linear part
Although it is a charp, the corners are slightly rounded and blurred C: Ink / peripheral area for both corner and straight part of enlarged character
The contrast is blurred Stability during continuous printing; the above print contents are continuously printed for 8 hours
Check for missing dots in the print during that time, and
It was similar A: No missing dots even after continuous printing for 8 hours B: Dot omission occurred during continuous printing for 1 to 8 hours C: Missing dots occur during continuous printing within 1 hour Clogging property: 7 days after the above printing is continued for 1 hour
Left for 1 hour, then print continuously for 1 hour, then 7 days
After leaving for a while, continuous printing was carried out for 1 hour. Each successive
Observe clogging in printing or missing dots
Then, it was classified as follows. A: No loss of dots even after left for 14 days in total
Can be printed well B: Missing dots occurred after printing 7 or 14 days later
Raw C: Printed after 7 days or 14 days due to clogging
Became impossible The results evaluated by the above method are shown in Table 2. Sample S1
In the tests using S3, good printing characteristics were
To η_maxIs 5 × 10^FiveSample S2 that exceeds mPa · s
In S3, it became clear that the ink characteristics were very good.
It was

(3) Comparative Examples 1 to 4 (Samples H1 to H4
Preparation and Evaluation) As a comparative sample, in the case where the viscosity modifier was not used in the formulation examples of Examples 1 to 3 (Sample H1), polyacrylamide (average molecular weight: 9) which is a water-soluble polymer as the viscosity modifier was used.
1,000,000 to 10,000,000, manufactured by Kishida Chemical Co., Ltd. (Sample H2), and two cases where cellulose that does not satisfy the conditions specified in the present invention is used as a viscosity modifier (Sample H).
3 and H4), ink compositions having the compositions shown in Table 1 were prepared in the same manner as in Examples 1 to 3. The cellulose used in Samples H3 and H4 was the following cellulose / water dispersion.

Sample H3 contains commercially available microcrystalline cellulose /
Aqueous dispersion, Theolus FP-03 ^™ (Cellulose concentration: 1
0% by weight, manufactured by Asahi Kasei Co., Ltd., was used as it was as a raw material. This white raw material dispersion is referred to as dispersion C. Sample H4
In addition, ultrapure water was added to the dispersion C to prepare a cellulose concentration of 4% by weight, and then T.I. K. Lobo. mi
15,000 rp using csTM (made by Tokushu Kika Co., Ltd.)
m for 10 minutes for pre-dispersion, and then ultra-high pressure homogenizer (Microfluidizer ^TM ,
A translucent white cellulose / water dispersion was prepared by treating M110-E / H type, manufactured by Mizuho Kogyo Co., Ltd., under a pressure of 1.72 × 10 ⁸ Pa five times, and preparing this. Used as raw material. The thus obtained cellulose / water dispersion having a cellulose concentration of 4% by weight is designated as Dispersion D.

The cellulose contained in Dispersions C and D both had an average degree of polymerization of 150 and a crystallinity of χ _I of 0.
65, χ _II was 0. Also, the average particle size is the value of Dispersion C
Cellulose of 5.0 μm and Cellulose of Dispersion D were 0.2 μm. The values of η _max of Samples H1 to H4 are shown in Table 1. Table 2 shows the results of evaluating the performance of the samples H1 to H4 as an ink composition for inkjet printing under the same conditions as in Examples 1 to 3. Sample H1 without addition of viscosity modifier (often also has dispersion stabilizing effect)
Bleeding easily occurs and the clogging property is poor. The ink composition thickened with a water-soluble polymer (Sample H2) was not suitable as an inkjet ink because the accuracy of the inkjet spraying was poor and it was difficult to form characters without bleeding. .

Further, in a system using cellulose having a particle size of more than 2 μm, there is still a problem in clogging property and printing accuracy during printing. The average particle size is submicron size, but the crystallinity is high. It was found that the sample H4, which has low transparency as a raw material cellulose dispersion, can print well, but is defective as an ink because of a problem in image density (coloring property). Furthermore, in the case of the ink composition using other than the cellulose of the present invention, a large improvement in resolution was not seen as compared with the case where the viscosity modifier was not added. These clarified the superiority of the ink composition of the present invention in a pigment-based ink composition having a relatively simple composition.

[0074]

Example 4 and Comparative Example 5 A dye-based ink composition
100 g each according to the following blending amount and preparation method 2
Different types were prepared, and the ink characteristics were compared according to the same evaluation criteria as in Examples 1-3. Sample S4; Acid dye (Red No. 104): 5.0 g, Sample A: 38 g,
n-Butanol: 2.0 g, ultrapure water: 55 g, Sample H5; Acid dye (Red No. 104): 5.0 g, Sample A: 13 g,
n-Butanol: 2.0 g, ultrapure water: 80 g After mixing various compounding components in a beaker, a homomixer (TK Lobo.mics ^™ , manufactured by Tokushu Kika Co., Ltd.) was used to obtain 5000 rpm. The dispersion treatment was performed for 10 minutes at the rotation speed of 1 and the defoaming treatment under reduced pressure was performed to obtain two types of ink compositions.

The cellulose content of each sample obtained was 1.5% by weight for sample S4 and 0.5% by weight for sample H5. The value of η _max of each sample was 2 × for sample S4. 10 ⁶ m
Pa · s and the sample H5 were 5.8 mPa · s. Since the sample S4 is the ink composition specified in the present invention, its preparation and evaluation are set as Example 4. In contrast, sample H5
Contains cellulose defined in the present invention, but does not satisfy the condition of η _max , and was evaluated as Comparative Example 5. The evaluation results are shown in Table 3. Sample H5 shows relatively good ink properties, but the ink composition of the present invention (Sample S4) in which the viscosity is controlled to be highly viscous has further excellent ink performance such as a large improvement in resolution and an improvement in each printing property. It became clear to show.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

EFFECTS OF THE INVENTION According to the present invention, despite being highly viscous, it has a high stability as a composition for ejection and a high anti-clogging property, and recording can be stably carried out on a target substance with high accuracy. (EN) Provided is a composition for inkjet discharge, which can be applied in a wide range of inkjet recording fields and which realizes improvement in expression resolution by miniaturization.

[Brief description of drawings]

FIG. 1 is an explanatory view for supplementing a wide-angle X-ray pattern and a method for obtaining h ₀ , h ₁ , h ₀ *, h ₁ * of cellulose of the present invention (dried body of sample A).

FIG. 2 is a viscosity-shear rate curve measured at 25 ° C. using a cone-plate type rotational viscometer for the ink composition provided by the present invention (Sample S3).

FIG. 3 is an explanatory diagram of a method for obtaining a viscosity-shear stress curve and η _max measured at 25 ° C. using a cone-plate type rotational viscometer for the ink composition provided by the present invention (Sample S3). .

Claims (3)

[Claims] 1. An average degree of polymerization (DP) of 100 or less, a cellulose I type crystal component fraction of 0.1 or less, a cellulose II type crystal component fraction of 0.4 or less, and a cellulose particle A composition for inkjet discharge containing cellulose fine particles having an average particle diameter of 2 μm or less, a liquid dispersion medium, and a functional compound, which is a cone of the composition.
Maximum value of viscosity in viscosity-shear stress curve obtained in shear rate region including at least 1 × 10 ⁻³ s ⁻¹ to 1 × 10 ² s ⁻¹ at 25 ° C. measured using a plate type rotational viscometer (Η _max ) is η _max ≧ 1 × 10 ³ mPa · s, the composition for inkjet discharge. 2. The composition for inkjet discharge according to claim 1, wherein the maximum value (η _max ) of the viscosity according to claim 1 is η _max ≧ 5 × 10 ⁵ mPa · s. 3. The composition for inkjet discharge according to claim 1, wherein the functional compound is a colorant.