JP2009067911A - Raw material for ink jet or ink for ink jet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a raw material for ink jet capable of efficiently performing filtration when the filtration is performed for removing at least a part of a material, attaining enhancement of productivity by shortening of a treatment time in the filtration and excellent in delivery stability and liquid stability, or an ink for ink jet, its manufacturing method, an ink using the raw material for ink jet, an ink cartridge using the ink, an ink jet printer, an image forming method, and an image formation article. <P>SOLUTION: In the raw material for ink jet or the ink for ink jet, the filtration is performed for removing at least a part of a component and the removal component is filtered/separated. In the manufacturing method for the raw material for ink jet or the ink for ink jet, the filtration of the liquid to be filtered is performed at a liquid temperature of 45°C or higher. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an inkjet raw material or an inkjet ink, and more specifically, when filtration is performed to remove at least a part of components, filtration can be performed efficiently, and discharge stability and liquid stability are excellent. The present invention relates to an ink jet raw material or an ink jet ink and a method for producing the same, an ink using the ink jet raw material, an ink cartridge using the ink, an ink jet printing apparatus, an image forming method, and an image formed article.
The ink-jet raw material or ink-jet ink of the present invention is particularly preferably used in an ink-jet recording method in which an ink is ejected and ejected as droplets from a fine ejection port to form an image on a recording medium. It can be widely used as ink for general writing instruments such as markers and water-based ballpoint pens, recorders, and pen plotters.

The inkjet recording method is easy to make full color because the process is simpler than other recording methods, and there is an advantage that a high-resolution image can be obtained even with an apparatus having a simple configuration.
As ink-jet inks, inks in which various colorants are mixed with water or water and an organic solvent or an organic solvent are used. When manufacturing these, filtration may be performed in order to remove at least some components. For that purpose, it is used to remove at least a part of excessive components and impurities.

As ink-jet inks, dye-based inks in which various water-soluble dyes are dissolved in water or a mixture of water and an organic solvent are mainly used, but dye-based inks have excellent color tone clarity. However, the light resistance was inferior.
On the other hand, pigment-based inks in which carbon black and various organic pigments are dispersed are actively studied because they are superior in light resistance compared to dye-based inks.
The pigment ink is generally prepared by preparing a dispersion in which a coloring material and a dispersant are pre-dispersed in an aqueous solvent such as water or alcohol, and then, using a sand mill media type disperser or the like, the dispersion is adjusted to a predetermined degree. Dispersion treatment is performed until a dispersion is prepared. Then, it is adjusted by diluting to a predetermined concentration.
In addition to the above dispersion liquids, there are dispersion liquids dispersed by a dispersion method such as a self-dispersion type or a microcapsule type.

  In recent years, it has been required to further reduce the particle size of the pigment contained in the ink in order to improve nozzle clogging, increase image density, improve color gamut, and improve definition. In pigment-based ink dispersion treatment, studies are being made to reduce the pigment particle size by selecting the type of dispersion machine, dispersion process conditions, and the like.

  However, the dispersion treatment alone cannot sufficiently reduce so-called coarse particles of about 1.0 μm or more, and many coarse particles remain in the dispersion. Therefore, it is not possible to sufficiently improve nozzle clogging, increase image density, improve color gamut, and improve definition.

Therefore, a proposal has been made to reduce coarse particles by performing filtration after the dispersion treatment. For example, Patent Document 1 (Japanese Patent No. 3880687), the filtration rate decay rate expressed as a specific function of the change in the filtrate weight is separated per each unit filtration time (filtration rate) is -0.02Sec ^{- It} proposes a method for producing a water-based ink for ink-jet that includes repeated filtration until it becomes ¹ or more.
However, the currently proposed filtration method has a problem that productivity is lowered due to a long processing time.
For example, in Patent Document 2 (Japanese Patent No. 3873044), for the purpose of stabilizing an increase in viscosity, heating aging is carried out by heating the ink composition after filtration at a temperature not lower than the temperature used in inkjet recording and not higher than 65 ° C. There has been proposed a method of manufacturing an ink for ink jet recording which performs the above. In this proposal, heat treatment is performed after filtration, and filtration is performed at room temperature. In this case, there is a problem that productivity is lowered due to a long filtration time.

Further, in Patent Document 3 (Japanese Patent No. 2980091), for the purpose of removing at least a part of the resin that is not adsorbed on the carbon black, the dispersion is heated to a temperature of 50 to 80 ° C. to form a resin on the carbon black. A method for producing an ink-jet ink comprising: a step of diluting an obtained dispersion by adding water and diluting and removing at least a part of the resin not adsorbed on carbon black by ultrafiltration Has been proposed. In this proposal, it is proposed that it is preferable to perform filtration under a temperature condition of 20 to 45 ° C. after heat treatment at a temperature of 50 to 80 ° C. to adsorb the resin to carbon black. Even in this case, filtration is proposed as a range up to 45 ° C., which is slightly higher than room temperature. However, there is a problem that productivity is lowered due to a long filtration time.
As described above, there are still problems in the filtration process, and improvements are required.

The present invention also provides an inkjet raw material that is centrifuged at a liquid temperature of 30 ° C. or higher in an inkjet raw material or inkjet ink that is centrifuged to remove at least some components. A raw material or inkjet ink has already been proposed (see Japanese Patent Application No. 2007-67642 of Patent Document 4).
As a result, the efficiency of the centrifugal treatment could be increased. However, since heating is not performed before the filtration, naturally, the filtration is performed in a state where the liquid temperature is lowered. Therefore, “filtration at a liquid temperature of 45 ° C. or higher” in the present invention is performed without heating. Even in the technique described in Patent Document 4, it has been found that the efficiency of filtration is still not sufficient, and there is a problem that the processing time in filtration is long and the productivity should be improved.
In addition, it has been found that when filtration is performed without performing the centrifugal treatment, the efficiency is low because it is not heated, and there is a problem that the processing time in filtration is long and productivity is deteriorated.

By the way, the present inventors separately remove the agglomerated foreign matter generated under long-term storage by heat-treating the dispersed liquid at a predetermined temperature for a predetermined time, and remove the water-based pigment dispersion and the water-based pigment ink. As a result of finding that it is also effective in suppressing changes in physical properties (particularly changes in viscosity and particle size), an aqueous pigment dispersion characterized by heat-treating an aqueous pigment dispersion containing at least a pigment, a dispersant, and water Has been proposed (see JP 2006-291169A).
However, since heating is not performed before the filtration, the filtration is naturally performed in a state where the liquid temperature is lowered. Therefore, the filtration according to the present invention is performed without heating, and the prior art described in Patent Document 5 is used. However, it has been found that the efficiency of filtration is still not sufficient, and there is a problem to be improved in terms of productivity due to the long processing time in filtration.

Japanese Patent No. 3880687 Japanese Patent No. 3873044 Japanese Patent No. 2980091 Japanese Patent Application No. 2007-67642 JP 2006-291169 A

This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives.
That is, the present invention relates to an ink-jet raw material or ink-jet ink, and more specifically, when filtration is performed to remove at least a part of the material, the filtration can be efficiently performed and the processing time in the filtration is shortened. Ink jet raw materials or ink jet inks excellent in ejection stability and liquid stability and manufacturing methods thereof, inks using the ink jet raw materials, ink cartridges using the inks, ink jet printing apparatuses, An object is to provide an image forming method and an image formed product.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by specifying the liquid temperature by filtration, and have reached the present invention.

That is, this invention is the following (1)-(21).
(1) “In order to remove at least a part of the components, filtration is performed at a liquid temperature of 45 ° C. or higher in an inkjet raw material or inkjet ink that is filtered to remove the removed components. Inkjet raw material or inkjet ink manufacturing method ",
(2) “The method for producing an ink-jet raw material or ink-jet ink according to item (1), wherein the liquid temperature during the filtration is 50 to 80 ° C.”,
(3) “The method for producing an ink-jet raw material or ink-jet ink according to item (1) or (2), wherein the filtration is performed at a pressure of 0.01 Mpa or more”;
(4) “The method for producing an ink-jet raw material or ink-jet ink according to item (1) or (2), wherein the filtration is performed at a pressure of 0.01 to 0.40 Mpa”;
(5) “The raw material for ink jet or the ink for ink jet according to any one of (1) to (4) above, wherein the filtration is performed with a filter pore size of 0.1 to 2.0 μm. Production method",
(6) “Inkjet raw material or inkjet ink according to any one of (1) to (5) above, wherein the viscosity at the liquid temperature at which the filtration is performed is 1000 mPa · s or less. Manufacturing method ",
(7) Any of the items (1) to (6), wherein the filtration is performed at a liquid temperature at which the viscosity at the liquid temperature at which the filtration is performed is 80% or less of the viscosity at 25 ° C. A method for producing the ink-jet raw material or ink-jet ink according to claim 1, "
(8) The means for raising the liquid temperature is used when performing the filtration treatment, and the means for raising the liquid temperature heats the inside of the apparatus for the filtration treatment. ) To (7), the ink-jet raw material or ink-jet ink manufacturing method ",
(9) The item (8), wherein the means for raising the liquid temperature during the filtration is used for heating the liquid before the filtration to raise the liquid temperature. Inkjet raw materials or inkjet ink production methods described in "
(10) The items (1) to (1), wherein the insoluble component is contained in an ink jet raw material and contains at least coarse particles of a pigment still remaining after the dispersion treatment of the pigment mixture. 9) The method for producing the ink-jet raw material or ink-jet ink according to any one of items
(11) “Manufacturing of raw material for ink jet or ink for ink jet according to item (10), wherein the content of the pigment before filtration is 2% by mass to 50% by mass when performing the filtration. Method",
(12) The raw material for inkjet according to item (10) or (11), wherein the content of the pigment before filtration is 20% by mass to 35% by mass when performing the filtration Alternatively, a method for producing an inkjet ink ",
(13) Any one of the above items (10) to (12), wherein the amount of the pigment removed after the filtration is 1 to 20% of the entire pigment content before the filtration. Inkjet raw materials or inkjet ink production methods described in "
(14) The raw material for inkjet according to any one of (10) to (13), wherein the pigment dispersion has an average particle diameter (D50) of 10 to 200 nm. Alternatively, a method for producing an inkjet ink ",
(15) “A method for producing an ink-jet raw material or ink-jet ink according to any one of items (1) to (14), wherein heat aging is performed before the filtration”,
(16) “Inkjet raw material or inkjet according to any one of (1) to (15) above, wherein filtration is performed at a liquid temperature of 45 ° C. or higher after centrifugation. Manufacturing method for ink ",
(17) The items (10) to (16), wherein the total number of pigment particles having a particle diameter of about 1.0 μm or more is reduced to 50% or less before filtration in the filtration. A method for producing an ink-jet raw material or ink-jet ink according to any one of "
(18) "Ink cartridge characterized by containing an ink-jet ink comprising the ink-jet ink according to any one of items (1) to (17)",
(19) “Inkjet, wherein recording is performed by ejecting an inkjet ink containing the inkjet ink according to any one of items (1) to (17) onto an image support. Printing device ",
(20) “An image forming method comprising printing with an inkjet printing apparatus using an inkjet ink comprising the inkjet ink according to any one of (1) to (17)” "
(21) “An image formed by an inkjet printing apparatus using the inkjet raw material or inkjet ink according to any one of (1) to (17)” "

  As is clear from the following detailed and specific description, coarse particles can be efficiently removed only in a short time and by the filtration treatment under specific liquid temperature conditions of the present invention. In addition, since the coarse particles can be efficiently reduced, the ink jet raw material or ink jet ink excellent in ejection stability and liquid stability can be obtained.

Hereinafter, the present invention will be described in more detail.
As a result of intensive studies on the solution of the above problems, the present inventors found that the temperature of the liquid during filtration is important together with the pressure in order to improve the efficiency of filtration. In general, the filtration is performed at a high liquid temperature of 45 ° C. or more, and the filtration can be efficiently performed. The productivity is improved by shortening the processing time in the filtration, the discharge stability, and the liquid. An ink jet raw material or ink jet ink having excellent stability and a method for producing the same, an ink using the ink jet raw material, an ink cartridge using the ink, an ink jet printing apparatus, an image forming method, and an image formed article can be obtained. We found out that we could do it and came to the present invention.
The timing of the filtration may be performed in the state of the raw material for inkjet, may be performed after the raw material is diluted with another solvent, or after other additives are added to the raw material. Alternatively, it may be performed after the ink is completely used.

  As described above, the present invention is characterized in that, in an inkjet raw material or inkjet ink that is filtered to remove at least a part of components, the filtration is performed at a liquid temperature of 45 ° C. or higher. Materials or ink-jet inks are provided. Below 45 ° C, the effect of improving the efficiency of filtration is small. More preferably, it is 50-80 degreeC. If the temperature is 50 ° C. or higher, the effect of increasing the filtration efficiency is further increased. If the temperature exceeds 80 ° C., the stability of the liquid may be adversely affected, and the solvent (moisture, etc.) may easily evaporate during filtration. is there.

For the filtration of the present invention, any filtration apparatus can be used as long as at least a part of the components can be removed by filtration.
For example, membrane, depth, ultrafiltration and the like can be mentioned.

The filtration pressure can be set as appropriate according to the purpose, but is 0.01 Mpa or more, more preferably 0.01 to 0.40 Mpa.
If it is 0.01 Mpa or less, the filtration efficiency is poor and the productivity is poor. If the pressure exceeds 0.40 Mpa, the pressure applied to the filter media is too strong, and the pore size of the filter may increase, or the filter life may be shortened.

  As long as the liquid temperature during filtration, which is a feature of the present invention, can be set to 50 ° C. or higher, any method may be used. Among them, as a means for raising the liquid temperature with a relatively simple structure, it is preferable to carry out by heating the inside of the apparatus for filtration. As a means for heating the inside of the apparatus, a heater or the like may be installed inside, or it may be heated from the outside of the filter. Moreover, the method of heating a liquid before performing filtration as another method can also be used suitably. As a means for heating the liquid in advance, the liquid before filtration may be heated in a tank and fed into the filter. Or the method etc. which send in the liquid which raised the liquid temperature by providing a heating part in the piping sent in to a filter machine, etc. are mentioned.

Other filtering conditions include filter pore diameter, and the filter pore diameter is such that the component to be removed can be removed to the target amount. However, if the filter pore size is made smaller than necessary, productivity will deteriorate and other effective components may be removed, and the stability of the liquid may be impaired. To do.
When used for inkjet, it is preferable to use a filter pore diameter of 0.1 to 2.0 μm in order to satisfy printing reliability such as clogging in the printer and bending in the ejection direction.
If the filter pore size is less than 0.1 μm, the filtration rate is slow, the filter life is short, the productivity is deteriorated, other effective components may be removed, and the stability of the liquid may be impaired.
When the filter hole diameter exceeds 2.0 μm, printing reliability such as clogging in the printer and bending in the ejection direction is poor.

In the ink-jet raw material or ink-jet ink, the viscosity at the liquid temperature at which filtration is performed is preferably 1000 mPa · s or less.
Although it is possible to perform filtration even when the pressure exceeds 1000 mPa · s, the processing time is long and the productivity is not good. In particular, when removing the coarse particles of the pigment, the pigment other than the coarse particles is filtered and the concentration of the pigment in the liquid after filtration tends to decrease. By setting the viscosity to 1000 mPa · s or less, a decrease in the pigment concentration after filtration can be improved.

In the ink-jet raw material or ink-jet ink, it is preferable to perform filtration at a liquid temperature at which the viscosity at the liquid temperature at which filtration is performed is 80% or less of the viscosity at 25 ° C.
In the present invention, the filtration can be efficiently performed by setting the liquid temperature to 45 ° C. or higher as compared with the case where the liquid temperature during filtration is normal temperature (room temperature, ambient temperature), that is, about 25 ° C. One of the factors is that the viscosity of the liquid decreases and the efficiency of filtration can be increased by increasing the liquid temperature.
Therefore, it is preferable to perform filtration at a liquid temperature that can lower the viscosity to a temperature that is 80% or less of the viscosity at 25 ° C., even at a liquid temperature of 45 ° C. or higher, thereby obtaining an effect of further increasing the efficiency of the filtration. I can do it. If the viscosity is lowered to 80%, the filtration efficiency can be increased by about 25%.
In addition, the viscosity in this invention can be measured with a conventionally well-known measuring method. For example, it can be measured using a viscometer RE-500U manufactured by Toki Sangyo Co., Ltd.
The filtration treatment of the present invention can be used to remove at least a part of excessively contained components, by-products, impurities, etc., from components dissolved or separated in a solvent. It can be suitably used to remove at least a part of. Examples of insoluble components include fine particles and coarse particles of various additives such as resins and antifoaming agents, impurities mixed in from various additives, and dust and dust mixed in during production. These insoluble components are more efficiently separated by filtration than dissolved components, and fine particles and coarse particles can be removed.

  Among them, it can be suitably used for removing coarse pigment particles from an inkjet material or an inkjet ink containing a pigment as an insoluble component and a dispersion treatment of the pigment mixture.

Dispersed pigment dispersion does not sufficiently reduce so-called coarse particles of about 0.5 μm or more by dispersion treatment alone even when dispersed to the desired particle size, and many coarse particles are present in the dispersion. Will remain. When removing these, it is necessary to remove only the pigment existing as coarse particles without removing the pigment dispersed to the target particle size as much as possible. At this time, only coarse particles can be efficiently and quickly separated by filtration under the conditions of the present invention. In addition, it is possible to suppress a decrease in the pigment concentration in the inkjet raw material or the inkjet ink after the filtration treatment, and it is possible to obtain an inkjet raw material or an inkjet ink that is excellent in ejection stability and liquid stability.
The timing of the filtration treatment may be performed in the state of the dispersion liquid dispersion, or may be performed after adding another additive to the dispersion liquid, or completely made into ink. You may go later.

When performing the filtration treatment, the content of the pigment before the filtration treatment is preferably 2% by mass to 50% by mass. When the amount is less than 2% by mass, the productivity is inferior. When the amount is more than 50% by mass, the dispersion treatment is difficult, the liquid stability tends to be inferior, and the efficiency in the filtration treatment is also inferior.
More preferably, it is 20 mass% to 35 mass%. When the content is 20% by mass or more, the productivity is further increased, and when the content is 35% or less, the dispersion treatment is facilitated.

  Moreover, when performing a filtration process, it is preferable that the quantity of the removal component (a pigment is mainly included) after a filtration process is 1 to 20% of the whole pigment content before a filtration process. If the removal amount is less than 1%, the coarse particles cannot be sufficiently removed, so that clogging and ejection stability are inferior. On the other hand, if more than 20% is removed, not only coarse particles but also pigments having a normal particle diameter are removed, resulting in poor productivity and high cost.

  The average particle diameter (D50) of the pigment can be appropriately selected according to the purpose, but is preferably 10 to 200 nm, and more preferably 20 to 150 nm. Compared with dyes, pigments are not dissolved in ink and dispersed as particles, so even inks with the same penetration characteristics are less likely to penetrate deep into paper, thus resulting in higher image density and less show-through. Good image quality can be obtained. However, when the average particle diameter (D50) is less than 10 nm, the pigment as the colorant penetrates deep into the paper, and thus the image density is low and the back-through may be greatly increased. The dispersion stability in the medium may be impaired, and the image density may be lowered during printing. If it is larger than 200 nm, the dispersion stability of the finally obtained ink is poor and the particle size becomes large due to aggregation or the like during long-term storage, resulting in poor ejection stability and clogging. Further, this is because the image density is inferior, the image fixing property is inferior, and the color saturation is deteriorated.

  In addition, the average particle diameter (D50) of the pigment in the present invention is diluted so that the pigment concentration becomes 0.1% using a particle size distribution measuring device “Microtrac UPA-EX150” manufactured by Nikkiso Co., Ltd. The volume average particle diameter (D50) is measured.

  The average particle diameter (D50) of the pigment particles is controlled by conditions such as the peripheral speed of the rotating part of the disperser, the dispersion time, the dispersion flow rate, and the dispersion temperature when the pigment is dispersed using the disperser. Can do.

As the type of the disperser, known dispersers such as a sand mill, a ball mill, a roll mill, a bead mill, a nanomizer, and a homogenizer can be used. At this time, it is preferable to employ a wet dispersion treatment.
The wet dispersion treatment is a treatment for finely pulverizing and dispersing a mixture of a pigment, a solvent, and if necessary, an organic solvent by a so-called wet dispersion method using the sand mill, ball mill, roll mill, bead mill, nanomizer, homogenizer, or the like. To tell.
In order to make the average particle diameter (D50) of the pigment particles 200 nm or less, if the peripheral speed of the rotating part of the disperser is too high, the pigment dispersion tends to aggregate. In view of this, it is preferable to set the speed to 6 m / s to 18 m / s.
Regarding the dispersion time when preparing the pigment dispersion for inkjet, the dispersion step may be terminated when the change in the average particle size of the dispersion liquid residence time in the dispersion portion is less than 2%. desirable. The dispersion flow rate is preferably 300 ml / min or more. This is because when the dispersion liquid flow rate is less than 300 ml / min, the dispersion temperature rises and the dispersion stability deteriorates.
When a bead mill is used as the disperser, the average particle diameter (D50) of the pigment particles can be controlled by adjusting the size of the dispersion medium (beads). In this case, in order to make the average particle diameter (D50) 200 nm or less, it is preferable to make the beads about 0.1 mm to 1.0 mm, and further, 0.1 mm to 0.5 mm.
The pigment dispersion type includes a dispersion by a dispersant, a self-dispersion type and a microcapsule type, and the filtration treatment of the present invention can be applied to any dispersion type.

  Depending on the formulation, it is preferable to perform a heat aging treatment on the ink-jet raw material or ink-jet ink before the filtration treatment. Although depending on the formulation, when the dispersion-treated liquid is stored for a long time, a part of the dispersed pigment may reagglomerate and coarse particles may increase. For this reason, by performing a heat aging treatment in advance, a pigment that re-aggregates when stored for a long time is re-agglomerated and coarsened in advance. Thereafter, the coarse particles can be removed by filtration, and an ink jet raw material or an ink jet ink can be obtained in which the coarse particles are prevented from increasing due to re-aggregation and the average particle diameter (D50) is prevented from increasing even when stored for a long time. I can do it. About the conditions of a heat aging process, you may determine arbitrarily by prescription. Generally, it is performed at about 35 to 80 ° C. for about 0.5 to 24 hours. The method may also be performed while the liquid is left standing or stirring, and the effect of the heat aging treatment may be obtained earlier when the liquid is stirred. Moreover, the method etc. which heat while circulating are also mentioned.

  The inkjet raw material or the inkjet ink is preferably subjected to a filtration treatment after being centrifuged. If the coarse particles are removed to some extent before the filtration by the centrifugal treatment, the productivity of the filtration filter increases and the filter life is extended. Depending on the type of centrifuge, some of the coarse particles lump settled in the centrifuge, or dust or dust may enter during or after the centrifuge. These are removed by filtration. Thereby, clogging can be prevented and the stability of the liquid can be improved.

In the filtration treatment, it is preferable to reduce the total number of pigment particles having a particle diameter of about 1.0 μm or more, preferably about 0.5 μm or more to 50% or less before the filtration treatment.
By setting it to ½ or less, the effect of removing coarse particles can be obtained, and it is possible to improve clogging, increase image density, improve color gamut, and improve definition. In the case of more than 1/4, the above-mentioned improvement effect is not sufficient because coarse particles are not sufficiently removed.
The measurement of the coarse particles having a size of 1.0 μm or more is not particularly limited, and can be performed by a method appropriately selected according to the purpose. For example, a number counting type particle size distribution measuring apparatus (manufactured by Particle Sizing Systems, “AccurSizer”). 780 ") or the like.

The pigment used in the ink-jet raw material or ink-jet ink of the present invention is preferably dispersed by a dispersant.
Among them, it is preferable to use at least one of the compounds represented by the following general formula (I) as the dispersant contained in the inkjet raw material or the inkjet ink of the present invention.
By using the compound represented by the general formula (I) as a dispersant, the dispersion stability of the pigment is increased, and the storage stability of the ink-jet raw material or ink-jet ink using each dispersant, particularly a liquid during high-temperature storage. The particle size stability and viscosity stability of the medium dispersed pigment particles are improved.

（式中、Ｒ１は炭素数１〜２０のアルキル基、アリル基、アラルキル基を表わし、ｌは０〜７の整数を、ｍは３０〜６０の整数を表わす。）

(In the formula, R1 represents an alkyl group having 1 to 20 carbon atoms, an allyl group, or an aralkyl group, l represents an integer of 0 to 7, and m represents an integer of 30 to 60.)

  Specific examples of the dispersant represented by formula (I) preferably used in the present invention are described below, but the present invention is not limited to these specific examples.

一般式（Ｉ）で表わされる化合物においてｍが２９以下もしくは６１以上であると、顔料分散時顔料の微粒子化分散が困難であり、３０以上、６０以下が好ましい。
分散剤と顔料の重量比は、分散顔料平均粒子径を２００ｎｍ以下の微粒子径に分散し、この粒子径を安定に保持するためには１／４〜５／４の範囲が好ましい。１／４よりも分散剤の量が少ない場合は、上記微小粒子径の顔料粒子が凝集しやすく、したがってインクの保存安定性が低下する。５／４よりも分散剤の量が多い場合は、インク粘度が高くなりすぎてプリントヘッドからのインク吐出が困難となる。

When m is 29 or less or 61 or more in the compound represented by the general formula (I), it is difficult to finely disperse the pigment when dispersing the pigment, and preferably 30 or more and 60 or less.
The weight ratio of the dispersant to the pigment is preferably in the range of 1/4 to 5/4 in order to disperse the dispersed pigment average particle diameter to a fine particle diameter of 200 nm or less and to keep this particle diameter stable. When the amount of the dispersant is less than 1/4, the pigment particles having the above-mentioned fine particle diameter are likely to aggregate, and therefore the storage stability of the ink is lowered. If the amount of the dispersant is larger than 5/4, the ink viscosity becomes too high, and it becomes difficult to eject ink from the print head.

As the dispersant, the compound of the general formula (I) can be most preferably used, but various other water-soluble resins and surfactants can be used.
As the water-soluble resin, a polymer that is soluble in an aqueous solution in which an amine or a base is dissolved and has a weight average molecular weight of 3000 to 30000, more preferably 5000 to 15000 can be used. Specifically, for example, natural polymers such as lignin sulfonate and shellac, styrene-acrylic acid-acrylic such as polyacrylic acid, styrene-acrylic acid copolymer, and styrene-acrylic acid-ethyl acrylate copolymer. Acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene-maleic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene -Maleic acid half ester copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, styrene-maleic anhydride-maleic acid half ester copolymer, salts of the above-mentioned copolymer, etc. It is done.
As the surfactant, an anionic, nonionic, cationic or amphoteric surfactant can be used.
Anionic surfactants include fatty acid salts, alkyl sulfate salts, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphates, Examples include polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxyethylene glycerol fatty acid ester, etc. The
Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid Nonionic surfactants such as esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, fluorine-based and silicon-based surfactants are exemplified.
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, alkylimidazolium salts and the like.
Examples of amphoteric surfactants include alkylbetaines, alkylamine oxides, phosphadylcholines and the like.
Of these, nonionic surfactants are more preferably used, and particularly the compounds of the above general formula (I), among which POE (n = 40) β naphthyl ether can be particularly preferably used.

Any of the pigments used in the ink-jet raw material or ink-jet ink of the present invention can be used. However, the pigments shown below are excellent in terms of color tone, light resistance, liquid stability and the like and can be preferably used.
Examples of the black pigment include carbon black produced by a furnace method or a channel method.
Examples of yellow pigments include Pig. Yellow pigments such as Pigment Yellow 1, Pigment Yellow 2, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 73, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 75, Pigment Yellow 83, Pigment Yellow 93, Pigment Yellow 95, Pigment Yellow 97, Pigment Yellow 98, Pigment Yellow 114, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 129, Pigment Yellow 138, Pigment Yellow 150 , Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 155 Pigment Yellow 180 and the like.
Examples of magenta pigments include Pig. Red pigments such as Pigment Red 5, Pigment Red 7, Pigment Red 12, Pigment Red 48 (Ca), Pigment Red 48 (Mn), Pigment Red 57 (Ca), and Pigment Red 57. 1: Pigment Red 112, Pigment Red 122, Pigment Red 123, Pigment Red 168, Pigment Red 184, Pigment Red 202, Pigment Violet 19 and the like.
Examples of cyan pigments include Pig. Blue pigments such as Pigment Blue 1, Pigment Blue 2, Pigment Blue 3, Pigment Blue 15, Pigment Blue 15: 3, Pigment Blue 15: 4, Pigment Blue 16, and Pigment Blue 22. Pigment Blue 60, Bat Blue 4, Bat Blue 60, and the like.
In particular, by using Pigment Yellow 74 as a yellow pigment, Pigment Red 122, Pigment Violet 19 as a magenta pigment, and Pigment Blue 15: 3 as a cyan pigment, an ink for ink-jet ink that has excellent color tone and light resistance and is balanced can be obtained. be able to.

In addition, for the ink-jet ink of the present invention, water, a water-soluble organic solvent, a surfactant, a preservative, an antifungal agent, etc. are appropriately selected as necessary to adjust the addition amount so as to meet the required ink characteristics It can be formulated by mixing and adjusting.
For example, as a water-soluble organic medium, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, Amides such as dimethylacetamide; Ketones or ketone alcohols such as acetone, methyl ethyl ketone, diacetone alcohol; Ethers such as tetrahydrofuran, dioxane; Ethylene glycol, propylene glycol, 1,2-propanediol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol Polyhydric alcohols such as glycerin; Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; Polyhydric glycols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether Lower alcohol ethers of alcohol; alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like. Among these, glycerin, ethylene glycol, diethylene glycol, 1,3-butanediol, triethylene glycol, and 2-pyrrolidone are particularly preferable from the viewpoints of safety and price. In addition, the content of the water-soluble organic solvent in the ink jet ink is preferably 50% by weight or less in consideration of environmental properties and the like.
Further, at least one additive selected from the group consisting of nonionic, anionic, cationic, amphoteric surfactants, preservatives, fungicides and the like may be added. Examples of preservatives include dehydroacetate, sorbate, benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, 2,4-dimethyl-6-acetoxy-m-dioxane, 1,2- A compound such as benzthiazolin-3-one can be given.

Furthermore, in addition to the above additives, a pH adjuster, a water-soluble resin, a resin emulsion, an antifoaming agent, an ultraviolet absorber and the like may be used as necessary.
In addition, the pigment content of the inkjet ink is preferably 2% by mass to 15% by mass. If it is less than 2% by mass, the effect of improving the saturation due to high density and small droplets cannot be obtained, and if it exceeds 15%, the ink viscosity is too high and it becomes difficult to eject ink from the print head. More preferably, it is 5.0-10 mass%.

The ink-jet ink of the present invention thus obtained is, for example, an ink set for ink-jet recording that forms an image on an image support by superimposing a plurality of inks of different hues in order to form a color image, and an ink containing the ink set It can be suitably used for a cartridge. Regarding the configuration of an ink cartridge containing the ink composition of the present invention, the configuration of an ink jet printing apparatus that performs recording by discharging the ink composition of the present invention, and the image forming method in the printing apparatus, the technology to which the present invention relates It can be easily carried out by referring to known techniques in the field, for example, those disclosed in JP-A-2000-198958.
The pigment-based ink-jet ink of the present invention can be image-formed by an ink-jet printing apparatus that forms an image by discharging (recording) the image on an image support such as paper.
Examples of a method for printing with this apparatus include a printing method using the above-described ink jet printer (ink jet printer) having a continuous jet type or on-demand type recording head. Note that examples of the on-demand type include a piezo method, a thermal ink jet method, and an electrostatic method.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In addition, the number of parts in an Example represents a mass part.
[Pigment dispersion preparation example 1]
Pigment Red 122 350 parts (Dainippon Ink, FASTOGEN SUPER MAGENTA RG, primary particle size 100 nm)
80 parts of the compound of general formula (I)
(L = 0, m = 40 POE position is β position)
570 parts of distilled water After premixing the above mixture, it was circulated and dispersed for 1 hour in a disk-type bead mill (Shinmaru Enterprises KDL-PA type, media: 0.3 mmφ zirconia ball used), and the average particle size was 82.4 nm. A pigment dispersion (A) was obtained.

[Pigment dispersion preparation example 2]
Pigment Blue 15: 3 300 copies
(Toyo Ink Manufacturing, LIONOL BLUE FG7351 primary particle size 30-50nm)
150 parts of the compound of general formula (I)
(L = 0, m = 40 POE position is β position)
Pionein A-51-B (Takemoto Yushi Co., Ltd.) 1 part
549 parts distilled water
After premixing the above mixture, it was circulated and dispersed for 11.5 hours in a disk-type bead mill (Shinmaru Enterprises KDL-PA type, media: 0.3 mmφ zirconia balls used), and then allowed to stand at 70 ° C. for 12 hours. Then, heat aging was performed to obtain a pigment dispersion (B) having an average particle diameter of 68.8 nm.

[Pigment dispersion preparation example 3]
Pigment Yellow 74 200 parts
(Manufactured by Dainichi Seika Co., Ltd., No. 43 average primary particle size 50 nm)
100 parts of the compound of general formula (I)
(L = 0, m = 40 POE position is β position)
700 parts distilled water
After premixing the above mixture, it was circulated and dispersed for 41 hours in a disk-type bead mill (Shinmaru Enterprises KDL-PA type, media: 0.3 mmφ zirconia balls used), and then heated at 70 ° C. with stirring for 2 hours. Aging was performed to obtain a pigment dispersion (C) having an average particle size of 56.3 nm.

[Pigment Dispersion Preparation Example 4]
150 parts of carbon black MCF88 (Mitsubishi Chemical Corporation)
100 parts of the compound of general formula (I)
(L = 0, m = 40 POE position is β position)
750 parts of distilled water After premixing the above mixture, it was circulated and dispersed for 41 hours in a disk type bead mill (Shinmaru Enterprises KDL-PA type, media: 0.3 mmφ zirconia ball used), and a pigment having an average particle size of 139 nm A dispersion (D) was obtained.

  Centrifugation was performed under the following conditions using the pigment dispersions (A) to (D) obtained by the above method.

Example 1
KS ultra high speed centrifuge model U1-160-H0 (front open type) manufactured by Kansai Centrifuge Co., Ltd., at room temperature, centrifugal force of 7000 G, circulation time of liquid in the centrifugal processing section The pigment dispersion (A) obtained by the above method was subjected to centrifugal treatment so that the time was 600 min. Thereafter, the obtained pigment dispersion liquid after centrifugation was wound around a filtration device with a heater, and the temperature of the liquid was adjusted to 45 ° C. with a 0.1 μm filter (Nippon Hall AB1V0017EYH). Filtration was performed at a pressure of 0.50 MPa.

(Example 2)
About the pigment dispersion liquid (B) obtained by the above method using a hybrid high-speed cooling centrifuge 6200 manufactured by Kubota Seisakusho Co., Ltd., setting the liquid temperature to 25 ° C., setting the centrifugal force to 7000 G, and the batch processing time to 300 minutes. Centrifugation was performed. Thereafter, the obtained pigment dispersion after centrifugation was heated to 50 ° C. in advance, and then filtered through a 0.45 μm filter (advantech Toyo TCG-045-S1PE) at a pressure of 0.30 MPa.

(Example 3)
KS ultra high speed centrifuge model U1-160-H0 (front open type) manufactured by Kansai Centrifuge Co., Ltd., at room temperature, centrifugal force of 7000 G, circulation time of liquid in the centrifugal processing section The pigment dispersion (C) obtained by the above method was subjected to a centrifugal treatment so that the time was 75 min. The resulting pigment dispersion after centrifugation was wrapped around a filtration device with a heater, and the temperature of the solution was adjusted to 60 ° C. with a 1.5 μm filter (AB1A0157J, Nippon Hall) At a pressure of 0.10 MPa. In addition, a heater was also wound around the tank in which the liquid before filtration was placed to enable heating temperature control, and the liquid temperature in the tank was also set to 60 ° C.

Example 4
KS ultra high speed centrifuge model U1-160-H0 (front open type) manufactured by Kansai Centrifuge Co., Ltd., at room temperature, centrifugal force of 7000 G, circulation time of liquid in the centrifugal processing section The pigment dispersion (D) obtained by the above method was subjected to a centrifugal treatment so as to be 50 min. Thereafter, the pigment dispersion after centrifugation was wound around a filtration device with a heater, and the temperature of the solution was adjusted to 80 ° C. with a 3.0 μm filter (AB1A0307J, manufactured by Nippon Hall) At a pressure of 0.10 MPa. In addition, a heater was also wound around the tank in which the liquid before filtration was placed to enable heating temperature control, and the liquid temperature in the tank was also set to 80 ° C.

Table 2 shows the results when Examples 1 to 4 were performed.
In addition, the viscosity measured the viscosity of the liquid in the state which used the viscometer RE-500U by Toki Sangyo Co., Ltd., and set the temperature of the thermostat to each temperature.
The total number of 0.5 μm or more was measured using a number counting type particle size distribution measuring apparatus (“AccuSizer 780” manufactured by Particle Sizing Systems), when 5 μl of the liquid to be measured was added.

(Comparative Example 1)
In Example 1, it carried out similarly except liquid temperature having been 25 degreeC.

(Comparative Example 2)
In Example 2, it carried out similarly except liquid temperature having been 25 degreeC.

(Comparative Example 3)
In Example 3, it carried out similarly except liquid temperature having been 25 degreeC.

(Comparative Example 4)
In Example 4, it carried out similarly except liquid temperature having been 25 degreeC.

表２のように、実施例の条件で行った場合のほうが、いずれも濾過後の０．５μｍ以上の粒径の顔料粒子の総個数が少なくなっており、２５℃で行った比較例より濾過処理の効率が良い。
また、濾過後の顔料濃度も比較例より実施例の方が高く、粗大粒子のみを効果的に除去できている。

As shown in Table 2, the total number of pigment particles having a particle diameter of 0.5 μm or more after filtration was smaller in the case where the treatment was performed under the conditions of the examples, and the filtration was performed more than in the comparative example conducted at 25 ° C. Processing efficiency is good.
Also, the pigment concentration after filtration is higher in the example than in the comparative example, and only coarse particles can be effectively removed.

Claims (21)

  Inkjet raw material or inkjet ink that is filtered to remove at least a part of the components, and the removed components are filtered, and the liquid to be filtered is filtered at a liquid temperature of 45 ° C. or higher. Raw material or ink jet ink manufacturing method.   The method for producing an ink-jet raw material or ink-jet ink according to claim 1, wherein the liquid temperature during the filtration is 50 to 80 ° C.   The method for producing an ink-jet raw material or ink-jet ink according to claim 1 or 2, wherein the filtration is performed at a pressure of 0.01 Mpa or more.   The method for producing an ink-jet raw material or ink-jet ink according to claim 1 or 2, wherein the filtration is performed at a pressure of 0.01 to 0.40 Mpa.   The method for producing an ink-jet raw material or ink-jet ink according to any one of claims 1 to 4, wherein the filtration is performed with a filter pore diameter of 0.1 to 2.0 µm.   The method for producing an ink-jet raw material or ink-jet ink according to any one of claims 1 to 5, wherein a viscosity at a liquid temperature at which the filtration is performed is 1000 mPa · s or less.   The ink-jet raw material or ink-jet ink according to any one of claims 1 to 6, wherein the filtration is performed at a liquid temperature at which the viscosity at the liquid temperature for performing the filtration is 80% or less of the viscosity at 25 ° C. Manufacturing method.   The means for raising the liquid temperature is used when performing the filtration treatment, and the means for raising the liquid temperature heats the inside of the apparatus for performing the filtration treatment. A method for producing an ink-jet raw material or ink-jet ink as described in 1.   9. The raw material for ink jet according to claim 8, wherein the means for raising the liquid temperature during the filtration is used for heating the liquid before the filtration, thereby raising the liquid temperature. A method for producing an inkjet ink.   10. The solvent according to claim 1, wherein a component insoluble in the solvent is contained in the raw material for inkjet, and contains at least coarse particles of the pigment still remaining in the pigment dispersion after the dispersion treatment of the pigment mixture. A method for producing an inkjet raw material or an inkjet ink according to any one of the above.   The method for producing an ink-jet raw material or ink-jet ink according to claim 10, wherein when the filtration is performed, the content of the pigment before the filtration is 2 mass% to 50 mass%.   The method for producing an ink-jet raw material or ink-jet ink according to claim 10 or 11, wherein when the filtration is performed, the content of the pigment before the filtration is 20 mass% to 35 mass%.   The amount of the pigment removed after the filtration is 1 to 20% of the total pigment content before the filtration, The ink-jet raw material or ink-jet ink according to any one of claims 10 to 12 Production method.   The method for producing an ink-jet raw material or ink-jet ink according to any one of claims 10 to 13, wherein the pigment dispersion has an average particle diameter (D50) of 10 to 200 nm.   The method for producing an ink-jet raw material or ink-jet ink according to any one of claims 1 to 14, wherein a heat aging treatment is performed before the filtration.   The method for producing an ink-jet raw material or ink-jet ink according to any one of claims 1 to 15, wherein after the centrifugal treatment, filtration is performed at a liquid temperature of 45 ° C or higher.   17. The inkjet raw material or inkjet according to claim 10, wherein the filtration reduces the total number of pigment particles having a particle diameter of about 1.0 μm or more to 50% or less before filtration. For producing ink for use.   An ink cartridge containing an ink jet ink comprising the ink jet ink according to claim 1.   An ink jet printing apparatus that performs recording by ejecting an ink jet ink containing the ink jet ink according to claim 1 onto an image support.   18. An image forming method comprising printing with an ink jet printing apparatus using the ink jet ink containing the ink jet ink according to claim 1.   An image formed by an inkjet printing apparatus using the inkjet raw material or the inkjet ink according to any one of claims 1 to 17.